SLsmg_fill_region

 SYNOPSIS
   Fill a rectangular region with a character

 USAGE
   void SLsmg_fill_region (r, c, nr, nc, ch)

       int r
       int c
       unsigned int nr
       unsigned int nc
       unsigned char ch


 DESCRIPTION
   The `SLsmg_fill_region' function may be used to a 
   rectangular region with the character `ch' in the current color.
   The rectangle's upper left corner is at row `r' and column
   `c', and spans `nr' rows and `nc' columns.  The position
   of the virtual cursor will be left at (`r', `c').

 SEE ALSO
   SLsmg_write_char, SLsmg_set_color
--------------------------------------------------------------

SLsmg_set_char_set

 SYNOPSIS
   Turn on or off line drawing characters

 USAGE
   void SLsmg_set_char_set (int a);

 DESCRIPTION
   `SLsmg_set_char_set' may be used to select or deselect the line drawing
   character set as the current character set.  If `a' is non-zero,
   the line drawing character set will be selected.  Otherwise, the
   standard character set will be selected.

 NOTES
   There is no guarantee that this function will actually enable the
   use of line drawing characters.  All it does is cause subsequent
   characters to be rendered using the terminal's alternate character
   set.  Such character sets usually contain line drawing characters.

 SEE ALSO
   SLsmg_write_char, SLtt_get_terminfo
--------------------------------------------------------------

int SLsmg_Scroll_Hash_Border;

 SYNOPSIS
   Set the size of the border for the scroll hash

 USAGE
   int SLsmg_Scroll_Hash_Border = 0;

 DESCRIPTION
   This variable may be used to ignore the characters that occur at the
   beginning and the end of a row when performing the hash calculation
   to determine whether or not a line has scrolled.  The default value
   is zero which means that all the characters on a line will be used.

 SEE ALSO
   SLsmg_refresh
--------------------------------------------------------------

SLsmg_suspend_smg

 SYNOPSIS
   Suspend screen management

 USAGE
   int SLsmg_suspend_smg (void)

 DESCRIPTION
   `SLsmg_suspend_smg' can be used to suspend the state of the
   screen management facility during suspension of the program.  Use of
   this function will reset the display back to its default state.  The
   funtion `SLsmg_resume_smg' should be called after suspension.  
   
   It returns zero upon success, or -1 upon error.
   
   This function is similar to `SLsmg_reset_smg' except that the
   state of the display prior to calling `SLsmg_suspend_smg' is saved.

 SEE ALSO
   SLsmg_resume_smg, SLsmg_reset_smg
--------------------------------------------------------------

SLsmg_resume_smg

 SYNOPSIS
   Resume screen management

 USAGE
   int SLsmg_resume_smg (void)

 DESCRIPTION
   `SLsmg_resume_smg' should be called after
   `SLsmg_suspend_smg' to redraw the display exactly like it was
   before `SLsmg_suspend_smg' was called.  It returns zero upon
   success, or -1 upon error.

 SEE ALSO
   SLsmg_suspend_smg
--------------------------------------------------------------

SLsmg_erase_eol

 SYNOPSIS
   Erase to the end of the row

 USAGE
   void SLsmg_erase_eol (void);

 DESCRIPTION
   `SLsmg_erase_eol' erases all characters from the current
   position to the end of the line.  The newly created space is given
   the color of the current color.  This function has no effect on the
   position of the virtual cursor.

 SEE ALSO
   SLsmg_gotorc, SLsmg_erase_eos, SLsmg_fill_region
--------------------------------------------------------------

SLsmg_gotorc

 SYNOPSIS
   Move the virtual cursor

 USAGE
   void SLsmg_gotorc (int r, int c)

 DESCRIPTION
   The `SLsmg_gotorc' function moves the virtual cursor to the row
   `r' and column `c'.  The first row and first column is
   specified by `r = 0' and `c = 0'.

 SEE ALSO
   SLsmg_refresh
--------------------------------------------------------------

SLsmg_erase_eos

 SYNOPSIS
   Erase to the end of the screen

 USAGE
   void SLsmg_erase_eos (void);

 DESCRIPTION
   The `SLsmg_erase_eos' is like `SLsmg_erase_eol' except that
   it erases all text from the current position to the end of the
   display.  The current color will be used to set the background of
   the erased area.

 SEE ALSO
   SLsmg_erase_eol
--------------------------------------------------------------

SLsmg_reverse_video

 SYNOPSIS
   Set the current color to 1

 USAGE
   void SLsmg_reverse_video (void);

 DESCRIPTION
   This function is nothing more than `SLsmg_set_color(1)'.  

 SEE ALSO
   SLsmg_set_color
--------------------------------------------------------------

SLsmg_set_color (int)

 SYNOPSIS
   Set the current color

 USAGE
   void SLsmg_set_color (int c);

 DESCRIPTION
   `SLsmg_set_color' is used to set the current color.  The
   parameter `c' is really a color object descriptor.  Actual
   foreground and background colors as well as other visual attributes
   may be associated with a color descriptor via the
   `SLtt_set_color' function.

 EXAMPLE
   This example defines color `7' to be green foreground on black
   background and then displays some text in this color:

         SLtt_set_color (7, NULL, "green", "black");
         SLsmg_set_color (7);
         SLsmg_write_string ("Hello");
         SLsmg_refresh ();


 NOTES
   It is important to understand that the screen managment routines
   know nothing about the actual colors associated with a color
   descriptor.  Only the descriptor itself is used by the `SLsmg'
   routines.  The lower level `SLtt' interface converts the color
   descriptors to actual colors.  Thus

         SLtt_set_color (7, NULL, "green", "black");
         SLsmg_set_color (7);
         SLsmg_write_string ("Hello");
         SLtt_set_color (7, NULL, "red", "blue");
         SLsmg_write_string ("World");
         SLsmg_refresh ();

   will result in `"hello"' displayed in red on blue and _not_
   green on black.

 SEE ALSO
   SLtt_set_color, SLtt_set_color_object
--------------------------------------------------------------

SLsmg_normal_video

 SYNOPSIS
   Set the current color to 0

 USAGE
   void SLsmg_normal_video (void);

 DESCRIPTION
   `SLsmg_normal_video' sets the current color descriptor to `0'.

 SEE ALSO
   SLsmg_set_color
--------------------------------------------------------------

SLsmg_printf

 SYNOPSIS
   Format a string on the virtual display

 USAGE
   void SLsmg_printf (char *fmt, ...)

 DESCRIPTION
   `SLsmg_printf' format a `printf' style variable argument
   list and writes it on the virtual display.  The virtual cursor will
   be moved to the end of the string.

 SEE ALSO
   SLsmg_write_string, SLsmg_vprintf
--------------------------------------------------------------

SLsmg_vprintf

 SYNOPSIS
   Format a string on the virtual display

 USAGE
   void SLsmg_vprintf (char *fmt, va_list ap)

 DESCRIPTION
   `SLsmg_vprintf' formats a string in the manner of _vprintf_
   and writes the result to the display.  The virtual cursor is
   advanced to the end of the string.

 SEE ALSO
   SLsmg_write_string, SLsmg_printf
--------------------------------------------------------------

SLsmg_write_string

 SYNOPSIS
   Write a character string on the display 

 USAGE
   void SLsmg_write_string (char *s)

 DESCRIPTION
   The function `SLsmg_write_string' displays the string `s' on
   the virtual display at the current position and moves the position
   to the end of the string.

 SEE ALSO
   SLsmg_printf, SLsmg_write_nstring
--------------------------------------------------------------

SLsmg_write_nstring

 SYNOPSIS
   Write the first n characters of a string on the display

 USAGE
   void SLsmg_write_nstring (char *s, unsigned int n);

 DESCRIPTION
   `SLsmg_write_nstring' writes the first `n' characters of
   `s' to this virtual display.  If the length of the string
   `s' is less than `n', the spaces will used until
   `n' characters have been written.  `s' can be `NULL', in
   which case `n' spaces will be written.

 SEE ALSO
   SLsmg_write_string, SLsmg_write_nchars
--------------------------------------------------------------

SLsmg_write_char

 SYNOPSIS
   Write a character to the virtual display

 USAGE
   void SLsmg_write_char (char ch);

 DESCRIPTION
   `SLsmg_write_char' writes the character `ch' to the virtual
   display.

 SEE ALSO
   SLsmg_write_nchars, SLsmg_write_string
--------------------------------------------------------------

SLsmg_write_nchars

 SYNOPSIS
   Write n characters to the virtual display

 USAGE
   void SLsmg_write_nchars (char *s, unsigned int n);

 DESCRIPTION
   `SLsmg_write_nchars' writes at most `n' characters from the
   string `s' to the display.  If the length of `s' is less
   than `n', the whole length of the string will get written.
   
   This function differs from `SLsmg_write_nstring' in that
   `SLsmg_write_nstring' will pad the string to write exactly
   `n' characters.  `SLsmg_write_nchars' does not perform any
   padding.

 SEE ALSO
   SLsmg_write_nchars, SLsmg_write_nstring
--------------------------------------------------------------

SLsmg_write_wrapped_string

 SYNOPSIS
   Write a string to the display with wrapping

 USAGE
   void SLsmg_write_wrapped_string (s, r, c, nr, nc, fill)

       char *s
       int r, c
       unsigned int nr, nc
       int fill


 DESCRIPTION
   `SLsmg_write_wrapped_string' writes the string `s' to the
   virtual display.  The string will be confined to the rectangular
   region whose upper right corner is at row `r' and column `c',
   and consists of `nr' rows and `nc' columns.  The string will
   be wrapped at the boundaries of the box.  If `fill' is non-zero,
   the last line to which characters have been written will get padded
   with spaces.

 NOTES
   This function does not wrap on word boundaries.  However, it will
   wrap when a newline charater is encountered.

 SEE ALSO
   SLsmg_write_string
--------------------------------------------------------------

SLsmg_cls

 SYNOPSIS
   Clear the virtual display

 USAGE
   void SLsmg_cls (void)

 DESCRIPTION
   `SLsmg_cls' erases the virtual display using the current color.
   This will cause the physical display to get cleared the next time
   `SLsmg_refresh' is called.

 NOTES
   This function is not the same as

        SLsmg_gotorc (0,0); SLsmg_erase_eos ();

   since these statements do not guarantee that the physical screen
   will get cleared.

 SEE ALSO
   SLsmg_refresh, SLsmg_erase_eos
--------------------------------------------------------------

SLsmg_refresh

 SYNOPSIS
   Update physical screen

 USAGE
   void SLsmg_refresh (void)

 DESCRIPTION
   The `SLsmg_refresh' function updates the physical display to
   look like the virtual display.

 SEE ALSO
   SLsmg_suspend_smg, SLsmg_init_smg, SLsmg_reset_smg
--------------------------------------------------------------

SLsmg_touch_lines

 SYNOPSIS
   Mark lines on the virtual display for redisplay

 USAGE
   void SLsmg_touch_lines (int r, unsigned int nr)

 DESCRIPTION
   `SLsmg_touch_lines' marks the `nr' lines on the virtual
   display starting at row `r' for redisplay upon the next call to
   `SLsmg_refresh'.

 NOTES
   This function should rarely be called, if ever.  If you find that
   you need to call this function, then your application should be
   modified to properly use the `SLsmg' screen management routines.
   This function is provided only for curses compatibility.

 SEE ALSO
   SLsmg_refresh
--------------------------------------------------------------

SLsmg_init_smg

 SYNOPSIS
   Initialize the var{SLsmg

 USAGE
   int SLsmg_init_smg (void)

 DESCRIPTION
   The `SLsmg_init_smg' function initializes the `SLsmg' screen
   management routines.   Specifically, this function allocates space
   for the virtual display and calls `SLtt_init_video' to put the
   terminal's physical display in the proper state.  It is up to the
   caller to make sure that the `SLtt' routines are initialized via
   `SLtt_get_terminfo' before calling `SLsmg_init_smg'.
   
   This function should also be called any time the size of the
   physical display has changed so that it can reallocate a new virtual
   display to match the physical display.
   
   It returns zero upon success, or -1 upon failure.

 SEE ALSO
   SLsmg_reset_smg
--------------------------------------------------------------

SLsmg_reset_smg

 SYNOPSIS
   Reset the var{SLsmg

 USAGE
   int SLsmg_reset_smg (void);

 DESCRIPTION
   `SLsmg_reset_smg' resets the `SLsmg' screen management
   routines by freeing all memory allocated while it was active.  It
   also calls `SLtt_reset_video' to put the terminal's display in
   it default state.

 SEE ALSO
   SLsmg_init_smg
--------------------------------------------------------------

SLsmg_char_at

 SYNOPSIS
   Get the character at the current position on the virtual display

 USAGE
   unsigned short SLsmg_char_at(void)

 DESCRIPTION
   The `SLsmg_char_at' function returns the character and its color
   at the current position on the virtual display.

 SEE ALSO
   SLsmg_read_raw, SLsmg_write_char
--------------------------------------------------------------

SLsmg_set_screen_start

 SYNOPSIS
   Set the origin of the virtual display

 USAGE
   void SLsmg_set_screen_start (int *r, int *c)

 DESCRIPTION
   `SLsmg_set_screen_start' sets the origin of the virtual display
   to the row `*r' and the column `*c'.  If either `r' or `c'
   is `NULL', then the corresponding value will be set to `0'.
   Otherwise, the location specified by the pointers will be updated to
   reflect the old origin.
   
   See \tt{slang/demo/pager.c} for how this function may be used to
   scroll horizontally.

 SEE ALSO
   SLsmg_init_smg
--------------------------------------------------------------

SLsmg_draw_hline

 SYNOPSIS
   Draw a horizontal line

 USAGE
   void SLsmg_draw_hline (unsigned int len)

 DESCRIPTION
   The `SLsmg_draw_hline' function draws a horizontal line of
   length `len' on the virtual display.  The position of the
   virtual cursor is left at the end of the line.

 SEE ALSO
   SLsmg_draw_vline
--------------------------------------------------------------

SLsmg_draw_vline

 SYNOPSIS
   Draw a vertical line

 USAGE
   void SLsmg_draw_vline (unsigned int len);

 DESCRIPTION
   The `SLsmg_draw_vline' function draws a vertical line of
   length `len' on the virtual display.  The position of the
   virtual cursor is left at the end of the line.

 SEE ALSO
   ??
--------------------------------------------------------------

SLsmg_draw_object

 SYNOPSIS
   Draw an object from the alternate character set

 USAGE
   void SLsmg_draw_object (int r, int c, unsigned char obj)

 DESCRIPTION
   The `SLsmg_draw_object' function may be used to place the object
   specified by `obj' at row `r' and column `c'.  The
   object is really a character from the alternate character set and
   may be specified using one of the following constants:

       SLSMG_HLINE_CHAR         Horizontal line 
       SLSMG_VLINE_CHAR         Vertical line 
       SLSMG_ULCORN_CHAR        Upper left corner 
       SLSMG_URCORN_CHAR        Upper right corner
       SLSMG_LLCORN_CHAR        Lower left corner
       SLSMG_LRCORN_CHAR        Lower right corner
       SLSMG_CKBRD_CHAR         Checkboard character
       SLSMG_RTEE_CHAR          Right Tee
       SLSMG_LTEE_CHAR          Left Tee
       SLSMG_UTEE_CHAR          Up Tee
       SLSMG_DTEE_CHAR          Down Tee
       SLSMG_PLUS_CHAR          Plus or Cross character


 SEE ALSO
   SLsmg_draw_vline, SLsmg_draw_hline, SLsmg_draw_box
--------------------------------------------------------------

SLsmg_draw_box

 SYNOPSIS
   Draw a box on the virtual display

 USAGE
   void SLsmg_draw_box (int r, int c, unsigned int dr, unsigned int dc)

 DESCRIPTION
   `SLsmg_draw_box' uses the `SLsmg_draw_hline' and
   `SLsmg_draw_vline' functions to draw a rectangular box on the
   virtual display.  The box's upper left corner is placed at row
   `r' and column `c'.  The width and length of the box is
   specified by `dc' and `dr', respectively.

 SEE ALSO
   SLsmg_draw_vline, SLsmg_draw_hline, SLsmg_draw_object
--------------------------------------------------------------

SLsmg_set_color_in_region

 SYNOPSIS
   Change the color of a specifed region

 USAGE
   void SLsmg_set_color_in_region (color, r, c, dr, dc)

     int color;
     int r, c;
     unsigned int dr, dc;


 DESCRIPTION
   `SLsmg_set_color_in_region' may be used to change the color of a
   rectangular region whose upper left corner is given by
   (`r',`c'), and whose width and height is given by `dc'
   and `dr', respectively.  The color of the region is given by the
   `color' parameter.

 SEE ALSO
   SLsmg_draw_box, SLsmg_set_color
--------------------------------------------------------------

SLsmg_get_column

 SYNOPSIS
   Get the column of the virtual cursor

 USAGE
   int SLsmg_get_column(void);

 DESCRIPTION
   The `SLsmg_get_column' function returns the current column of
   the virtual cursor on the virtual display.

 SEE ALSO
   SLsmg_get_row, SLsmg_gotorc
--------------------------------------------------------------

SLsmg_get_row

 SYNOPSIS
   Get the row of the virtual cursor

 USAGE
   int SLsmg_get_row(void);

 DESCRIPTION
   The `SLsmg_get_row' function returns the current row of the
   virtual cursor on the virtual display.

 SEE ALSO
   SLsmg_get_column, SLsmg_gotorc
--------------------------------------------------------------

SLsmg_forward

 SYNOPSIS
   Move the virtual cursor forward n columns

 USAGE
   void SLsmg_forward (int n);

 DESCRIPTION
   The `SLsmg_forward' function moves the virtual cursor forward
   `n' columns.

 SEE ALSO
   SLsmg_gotorc
--------------------------------------------------------------

SLsmg_write_color_chars

 SYNOPSIS
   Write characters with color descriptors to virtual display

 USAGE
   void SLsmg_write_color_chars (unsigned short *s, unsigned int len)

 DESCRIPTION
   The `SLsmg_write_color_chars' function may be used to write
   `len' characters, each with a different color descriptor to the
   virtual display.  Each character and its associated color are
   encoded as an `unsigned short' such that the lower eight bits
   form the character and the next eight bits form the color.

 SEE ALSO
   SLsmg_char_at, SLsmg_write_raw
--------------------------------------------------------------

SLsmg_read_raw

 SYNOPSIS
   Read characters from the virtual display

 USAGE
   unsigned int SLsmg_read_raw (unsigned short *buf, unsigned int len)

 DESCRIPTION
   `SLsmg_read_raw' attempts to read `len' characters from the
   current position on the virtual display into the buffer specified by
   `buf'.  It returns the number of characters actually read.  This
   number will be less than `len' if an attempt is made to read
   past the right margin of the display.

 NOTES
   The purpose of the pair of functions, `SLsmg_read_raw' and
   `SLsmg_write_raw', is to permit one to copy the contents of one
   region of the virtual display to another region.

 SEE ALSO
   SLsmg_char_at, SLsmg_write_raw
--------------------------------------------------------------

SLsmg_write_raw

 SYNOPSIS
   Write characters directly to the virtual display

 USAGE
   unsigned int SLsmg_write_raw (unsigned short *buf, unsigned int len)

 DESCRIPTION
   The `SLsmg_write_raw' function attempts to write `len'
   characters specified by `buf' to the display at the current
   position.  It returns the number of characters successfully written,
   which will be less than `len' if an attempt is made to write
   past the right margin.

 NOTES
   The purpose of the pair of functions, `SLsmg_read_raw' and
   `SLsmg_write_raw', is to permit one to copy the contents of one
   region of the virtual display to another region.

 SEE ALSO
   SLsmg_read_raw
--------------------------------------------------------------

SLallocate_load_type

 SYNOPSIS
   Allocate a SLang_Load_Type object

 USAGE
   SLang_Load_Type *SLallocate_load_type (char *name)

 DESCRIPTION
   The `SLallocate_load_type' function allocates and initializes
   space for a `SLang_Load_Type' object and returns it.  Upon
   failure, the function returns `NULL'.  The parameter `name'
   must uniquely identify the object.  For example, if the object
   represents a file, then `name' could be the absolute path name
   of the file.

 SEE ALSO
   SLdeallocate_load_type, SLang_load_object
--------------------------------------------------------------

SLdeallocate_load_type

 SYNOPSIS
   Free a SLang_Load_Type object

 USAGE
   void SLdeallocate_load_type (SLang_Load_Type *slt)

 DESCRIPTION
   This function frees the memory associated with a
   `SLang_Load_Type' object that was acquired from a call to the
   `SLallocate_load_type' function.

 SEE ALSO
   SLallocate_load_type, SLang_load_object
--------------------------------------------------------------

SLang_load_object

 SYNOPSIS
   Load an object into the interpreter

 USAGE
   int SLang_load_object (SLang_Load_Type *obj)

 DESCRIPTION
   The function `SLang_load_object' is a generic function that may
   be used to loaded an object of type `SLang_Load_Type' into the
   interpreter.  For example, the functions `SLang_load_file' and
   `SLang_load_string' are wrappers around this function to load a
   file and a string, respectively.

 SEE ALSO
   SLang_load_file, SLang_load_string, SLallocate_load_type
--------------------------------------------------------------

SLclass_allocate_class

 SYNOPSIS
   Allocate a class for a new data type

 USAGE
   SLang_Class_Type *SLclass_allocate_class (char *name)

 DESCRIPTION
   The purpose of this function is to allocate and initialize space
   that defines a new data type or class called `name'.  If
   successful, a pointer to the class is returned, or upon failure the
   function returns `NULL'.
   
   This function does not automatically create the new data type.
   Callback functions must first be associated with the data type via
   functions such as `SLclass_set_push_function', and the data
   type must be registered with the interpreter via
   `SLclass_register_class'.  See the S-Lang library programmer's
   guide for more information.

 SEE ALSO
   SLclass_register_class, SLclass_set_push_function
--------------------------------------------------------------

SLclass_register_class

 SYNOPSIS
   Register a new data type with the interpreter

 USAGE
   int SLclass_register_class (cl, type, sizeof_type, class_type)

       SLang_Class_Type *cl
       unsigned char type
       unsigned int sizeof_type
       unsigned char class_type


 DESCRIPTION
   The `SLclass_register_class' function is used to register a new
   class or data type with the interpreter.  If successful, the
   function returns `0', or upon failure, it returns `-1'.
   
   The first parameter, `cl', must have been previously obtained
   via the `SLclass_allocate_class' function.
   
   The second parameter, `type' specifies the data type of the new
   class.  It must be an unsigned character with value greater that
   `127'.  The values in the range `0-127' are reserved for
   internal use by the library.
   
   The size that the data type represents in bytes is specified by the
   third parameter, `sizeof_type'.   This value should not be
   confused with the sizeof the structure that represents the data
   type, unless the data type is of class `SLANG_CLASS_TYPE_VECTOR'
   or `SLANG_CLASS_TYPE_SCALAR'.  For pointer objects, the value
   of this parameter is just `sizeof(void *)'.
   
   The final parameter specifies the class type of the data type.  It must
   be one of the values:

        SLANG_CLASS_TYPE_SCALAR
        SLANG_CLASS_TYPE_VECTOR
        SLANG_CLASS_TYPE_PTR
        SLANG_CLASS_TYPE_MMT

   The `SLANG_CLASS_TYPE_SCALAR' indicates that the new data type
   is a scalar.  Examples of scalars in `SLANG_INT_TYPE' and
   `SLANG_DOUBLE_TYPE'.
   
   Setting `class_type' to SLANG_CLASS_TYPE_VECTOR implies that the
   new data type is a vector, or a 1-d array of scalar types.  An
   example of a data type of this class is the
   `SLANG_COMPLEX_TYPE', which represents complex numbers.
   
   `SLANG_CLASS_TYPE_PTR' specifies the data type is of a pointer
   type.  Examples of data types of this class include
   `SLANG_STRING_TYPE' and `SLANG_ARRAY_TYPE'.  Such types must
   provide for their own memory management.
   
   Data types of class `SLANG_CLASS_TYPE_MMT' are pointer types
   except that the memory management, i.e., creation and destruction of
   the type, is handled by the interpreter.  Such a type is called a
   _memory managed type_.  An example of this data type is the
   `SLANG_FILEPTR_TYPE'.

 NOTES
   See the \slang-c-programmers-guide for more information.

 SEE ALSO
   SLclass_allocate_class
--------------------------------------------------------------

SLclass_set_string_function

 SYNOPSIS
   Set a data type's string representation callback

 USAGE
   int SLclass_set_string_function (cl, sfun)

      SLang_Class_Type *cl
      char *(*sfun) (unsigned char, VOID_STAR);


 DESCRIPTION
   The `SLclass_set_string_function' routine is used to define a
   callback function, `sfun', that will be used when a string
   representation of an object of the data type represented by `cl'
   is needed.  `cl' must have already been obtained via a call to
   `SLclass_allocate_class'.  When called, `sfun' will be
   passed two arguments: a unsigned char which represents the data
   type, and the address of the object for which a string represetation
   is required.  The callback function must return a _malloced_
   string.
   
   Upon success, `SLclass_set_string_function' returns zero, or
   upon error it returns -1.

 EXAMPLE
   A callback function that handles both `SLANG_STRING_TYPE' and
   `SLANG_INT_TYPE' variables looks like:

        char *string_and_int_callback (unsigned char type, VOID_STAR addr)
        {
           char buf[64];
   
   	switch (type)
   	  {
   	     case SLANG_STRING_TYPE:
   	       return SLmake_string (*(char **)addr);
   	     
   	     case SLANG_INTEGER_TYPE:
   	       sprintf (buf, "%d", *(int *)addr);
   	       return SLmake_string (buf);
             }
           return NULL;
        }


 NOTES
   The default string callback simply returns the name of the data type.

 SEE ALSO
   SLclass_allocate_class, SLclass_register_class
--------------------------------------------------------------

SLclass_set_destroy_function

 SYNOPSIS
   Set the destroy method callback for a data type

 USAGE
   int SLclass_set_destroy_function (cl, destroy_fun)

       SLang_Class_Type *cl
       void (*destroy_fun) (unsigned char, VOID_STAR);


 DESCRIPTION
   `SLclass_set_destroy_function' is used to set the destroy
   callback for a data type.  The data type's class `cl' must have
   been previously obtained via a call to `SLclass_allocate_class'.
   When called, `destroy_fun' will be passed two arguments: a
   unsigned char which represents the data type, and the address of the
   object to be destroyed.
   
   `SLclass_set_destroy_function' returns zero upon success, and
   -1 upon failure.

 EXAMPLE
   The destroy method for `SLANG_STRING_TYPE' looks like:

       static void string_destroy (unsigned char type, VOID_STAR ptr)
       {
          char *s = *(char **) ptr;
          if (s != NULL) SLang_free_slstring (*(char **) s);
       }


 NOTES
   Data types of class SLANG_CLASS_TYPE_SCALAR do not require a destroy
   callback.  However, other classes do.

 SEE ALSO
   SLclass_allocate_class, SLclass_register_class
--------------------------------------------------------------

SLclass_set_push_function

 SYNOPSIS
   Set the push callback for a new data type

 USAGE
   int SLclass_set_push_function (cl, push_fun)

       SLang_Class_Type *cl
       int (*push_fun) (unsigned char, VOID_STAR);


 DESCRIPTION
   `SLclass_set_push_function' is used to set the push callback
   for a new data type specified by `cl', which must have been
   previously obtained via `SLclass_allocate_class'.
   
   The parameter `push_fun' is a pointer to the push callback.  It
   is required to take two arguments: an unsigned character
   representing the data type, and the address of the object to be
   pushed.  It must return zero upon success, or -1 upon failure.
   
   `SLclass_set_push_function' returns zero upon success, or -1
   upon failure.

 EXAMPLE
   The push callback for `SLANG_COMPLEX_TYPE' looks like:

         static int complex_push (unsigned char type, VOID_STAR ptr)
         {
            double *z = *(double **) ptr;
            return SLang_push_complex (z[0], z[1]);
         }


 SEE ALSO
   SLclass_allocate_class, SLclass_register_class
--------------------------------------------------------------

SLclass_set_pop_function

 SYNOPSIS
   Set the pop callback for a new data type

 USAGE
   int SLclass_set_pop_function (cl, pop_fun)

       SLang_Class_Type *cl
       int (*pop_fun) (unsigned char, VOID_STAR);


 DESCRIPTION
   `SLclass_set_pop_function' is used to set the callback for
   popping an object from the stack for a new data type specified by
   `cl', which must have been previously obtained via
   `SLclass_allocate_class'. 
   
   The parameter `pop_fun' is a pointer to the pop callback
   function, which is required to take two arguments: an unsigned
   character representing the data type, and the address of the object
   to be popped.  It must return zero upon success, or -1 upon
   failure.
   
   `SLclass_set_pop_function' returns zero upon success, or -1
   upon failure.

 EXAMPLE
   The pop callback for `SLANG_COMPLEX_TYPE' looks like:

         static int complex_push (unsigned char type, VOID_STAR ptr)
         {
            double *z = *(double **) ptr;
            return SLang_pop_complex (&z[0], &z[1]);
         }


 SEE ALSO
   SLclass_allocate_class, SLclass_register_class
--------------------------------------------------------------

SLclass_get_datatype_name

 SYNOPSIS
   Get the name of a data type

 USAGE
   char *SLclass_get_datatype_name (unsigned char type)

 DESCRIPTION
   The `SLclass_get_datatype_name' function returns the name of the
   data type specified by `type'.  For example, if `type' is
   `SLANG_INT_TYPE', the string `"Integer_Type"' will be
   returned.
   
   This function returns a pointer that should not be modified or freed.

 SEE ALSO
   SLclass_allocate_class, SLclass_register_class
--------------------------------------------------------------

SLang_free_mmt

 SYNOPSIS
   Free a memory managed type

 USAGE
   void SLang_free_mmt (SLang_MMT_Type *mmt)

 DESCRIPTION
   The `SLang_MMT_Type' function is used to free a memory managed
   data type.

 SEE ALSO
   SLang_object_from_mmt, SLang_create_mmt
--------------------------------------------------------------

SLang_object_from_mmt

 SYNOPSIS
   Get a pointer to the value of a memory managed type

 USAGE
   VOID_STAR SLang_object_from_mmt (SLang_MMT_Type *mmt)

 DESCRIPTION
   The `SLang_object_from_mmt' function returns a pointer to the
   actual object whose memory is being managed by the interpreter.

 SEE ALSO
   SLang_free_mmt, SLang_create_mmt
--------------------------------------------------------------

SLang_create_mmt

 SYNOPSIS
   Create a memory managed data type

 USAGE
   SLang_MMT_Type *SLang_create_mmt (unsigned char t, VOID_STAR ptr)

 DESCRIPTION
   The `SLang_create_mmt' function returns a pointer to a new
   memory managed object.  This object contains information necessary
   to manage the memory associated with the pointer `ptr' which
   represents the application defined data type of type `t'.

 SEE ALSO
   SLang_object_from_mmt, SLang_push_mmt, SLang_free_mmt
--------------------------------------------------------------

SLang_push_mmt

 SYNOPSIS
   Push a memory managed type

 USAGE
   int SLang_push_mmt (SLang_MMT_Type *mmt)

 DESCRIPTION
   This function is used to push a memory managed type onto the
   interpreter stack.  It returns zero upon success, or `-1' upon
   failure.

 SEE ALSO
   SLang_create_mmt, SLang_pop_mmt
--------------------------------------------------------------

SLang_pop_mmt

 SYNOPSIS
   Pop a memory managed data type

 USAGE
   SLang_MMT_Type *SLang_pop_mmt (unsigned char t)

 DESCRIPTION
   The `SLang_pop_mmt' function may be used to pop a memory managed
   type of type `t' from the stack.  It returns a pointer to the
   memory managed object upon success, or `NULL' upon failure.  The
   function `SLang_object_from_mmt' should be used to access the
   actual pointer to the data type.

 SEE ALSO
   SLang_object_from_mmt, SLang_push_mmt
--------------------------------------------------------------

SLang_inc_mmt

 SYNOPSIS
   Increment a memory managed type reference count

 USAGE
   void SLang_inc_mmt (SLang_MMT_Type *mmt);

 DESCRIPTION
   The `SLang_inc_mmt' function may be used to increment the
   reference count associated with the memory managed data type given
   by `mmt'.

 SEE ALSO
   SLang_free_mmt, SLang_create_mmt, SLang_pop_mmt, SLang_pop_mmt
--------------------------------------------------------------

SLang_vmessage

 SYNOPSIS
   Display a message to the message device

 USAGE
   void SLang_vmessage (char *fmt, ...)

 DESCRIPTION
   This function prints a `printf' style formatted variable
   argument list to the message device.  The default message device is
   `stdout'.

 SEE ALSO
   SLang_verror
--------------------------------------------------------------

SLang_exit_error

 SYNOPSIS
   Exit the program and display an error message

 USAGE
   void SLang_exit_error (char *fmt, ...)

 DESCRIPTION
   The `SLang_exit_error' function terminates the program and
   displays an error message using a `printf' type variable
   argument list.  The default behavior to this function is to write
   the message to `stderr' and exit with the `exit' system
   call. 
   
   If the function pointer `SLang_Exit_Error_Hook' is
   non-NULL, the function to which it points will be called.  This
   permits an application to perform whatever cleanup is necessary.
   This hook has the prototype:

        void (*SLang_Exit_Error_Hook)(char *, va_list);


 SEE ALSO
   SLang_verror, exit
--------------------------------------------------------------

SLang_init_slang

 SYNOPSIS
   Initialize the interpreter

 USAGE
   int SLang_init_slang (void)

 DESCRIPTION
   The `SLang_init_slang' function must be called by all
   applications that use the S-Lang interpreter.  It initializes the
   interpreter, defines the built-in data types, and adds a set of core
   intrinsic functions.
   
   The function returns `0' upon success, or `-1' upon failure.

 SEE ALSO
   SLang_init_slfile, SLang_init_slmath, SLang_init_slunix
--------------------------------------------------------------

SLang_init_slfile

 SYNOPSIS
   Initialize the interpreter file I/O intrinsics

 USAGE
   int SLang_init_slfile (void)

 DESCRIPTION
   This function initializes the interpreters file I/O intrinsic
   functions.  This function adds intrinsic functions such as
   `fopen', `fclose', and `fputs' to the interpreter.
   It returns `0' if successful, or `-1' upon error.

 NOTES
   Before this function can be called, it is first necessary to call
   `SLang_init_slang'.  It also adds
   the preprocessor symbol `__SLFILE__' to the interpreter.

 SEE ALSO
   SLang_init_slang, SLang_init_slunix, SLang_init_slmath
--------------------------------------------------------------

SLang_init_slmath

 SYNOPSIS
   Initialize the interpreter math intrinsics

 USAGE
   int SLang_init_slmath (void)

 DESCRIPTION
   The `SLang_init_slmath' function initializes the interpreter's
   mathematical intrinsic functions and makes them available to the
   language.  The intrinsic functions include `sin', `cos',
   `tan', etc...  It returns `0' if successful, or `-1'
   upon failure.

 NOTES
   This function must be called after `SLang_init_slang'.  It adds
   the preprocessor symbol `__SLMATH__' to the interpreter.

 SEE ALSO
   SLang_init_slang, SLang_init_slfile, SLang_init_slunix
--------------------------------------------------------------

SLang_init_slunix

 SYNOPSIS
   Make available some unix system calls to the interpreter

 USAGE
   int SLang_init_slunix (void)

 DESCRIPTION
   The `SLang_init_slunix' function initializes the interpreter's
   unix system call intrinsic functions and makes them available to the
   language.  Examples of functions made available by
   `SLang_init_slunix' include `chmod', `chown', and
   `stat_file'.  It returns `0' if successful, or `-1'
   upon failure.

 NOTES
   This function must be called after `SLang_init_slang'.  It adds
   the preprocessor symbol `__SLUNIX__' to the interpreter.

 SEE ALSO
   SLang_init_slang, SLang_init_slfile, SLang_init_slmath
--------------------------------------------------------------

SLadd_intrin_fun_table

 SYNOPSIS
   Add a table of intrinsic functions to the interpreter

 USAGE
   int SLadd_intrin_fun_table(SLang_Intrin_Fun_Type *tbl, char *pp_name);

 DESCRIPTION
   The `SLadd_intrin_fun_table' function adds an array, or table, of
   `SLang_Intrin_Fun_Type' objects to the interpreter.  The first
   parameter, `tbl' specifies the table to be added.  The second
   parameter `pp_name', if non-NULL will be added to the list of
   preprocessor symbols.
   
   This function returns -1 upon failure or zero upon success.

 NOTES
   A table should only be loaded one time and it is considered to be an
   error on the part of the application if it loads a table more than
   once.

 SEE ALSO
   SLadd_intrin_var_table, SLadd_intrinsic_function, SLdefine_for_ifdef
--------------------------------------------------------------

SLadd_intrin_var_table

 SYNOPSIS
   Add a table of intrinsic variables to the interpreter

 USAGE
   int SLadd_intrin_var_table (SLang_Intrin_Var_Type *tbl, char *pp_name);

 DESCRIPTION
   The `SLadd_intrin_var_table' function adds an array, or table, of
   `SLang_Intrin_Var_Type' objects to the interpreter.  The first
   parameter, `tbl' specifies the table to be added.  The second
   parameter `pp_name', if non-NULL will be added to the list of
   preprocessor symbols.
   
   This function returns -1 upon failure or zero upon success.

 NOTES
   A table should only be loaded one time and it is considered to be an
   error on the part of the application if it loads a table more than
   once.

 SEE ALSO
   SLadd_intrin_var_table, SLadd_intrinsic_function, SLdefine_for_ifdef
--------------------------------------------------------------

SLang_load_file

 SYNOPSIS
   Load a file into the interpreter

 USAGE
   int SLang_load_file (char *fn)

 DESCRIPTION
   The `SLang_load_file' function opens the file whose name is
   specified by `fn' and feeds it to the interpreter, line by line,
   for execution.  If `fn' is `NULL', the function will take
   input from `stdin'.
   
   If no error occurs, it returns `0'; otherwise,
   it returns `-1', and sets `SLang_Error' accordingly.  For
   example, if it fails to open the file, it will return `-1' with
   `SLang_Error' set to `SL_OBJ_NOPEN'.

 NOTES
   If the hook `SLang_Load_File_Hook' declared as

         int (*SLang_Load_File_Hook)(char *);

   is non-NULL, the function point to by it will be used to load the
   file.  For example, the jed editor uses this hook to load files
   via its own routines.

 SEE ALSO
   SLang_load_object, SLang_load_string
--------------------------------------------------------------

SLang_restart

 SYNOPSIS
   Reset the interpreter after an error

 USAGE
   void SLang_restart (int full)

 DESCRIPTION
   The `SLang_restart' function should be called by the
   application at top level if an error occurs.  If the parameter
   `full' is non-zero, any objects on the S-Lang run time stack
   will be removed from the stack; otherwise, the stack will be left
   intact.  Any time the stack is believed to be trashed, this routine
   should be called with a non-zero argument (e.g., if
   `setjmp'/`longjmp' is called).
   
   Calling `SLang_restart' does not reset the global variable
   `SLang_Error' to zero.  It is up to the application to reset
   that variable to zero after calling `SLang_restart'.

 EXAMPLE

         while (1)
           {
   	   if (SLang_Error) 
   	     {
   	        SLang_restart (1);
   		SLang_Error = 0;
   	     }
   	   (void) SLang_load_file (NULL);
   	}


 SEE ALSO
   SLang_init_slang, SLang_load_file
--------------------------------------------------------------

SLang_byte_compile_file

 SYNOPSIS
   Byte-compile a file for faster loading

 USAGE
   int SLang_byte_compile_file(char *fn, int reserved)

 DESCRIPTION
   The `SLang_byte_compile_file' function ``byte-compiles'' the
   file `fn' for faster loading by the interpreter.  This produces
   a new file whose filename is equivalent to the one specified by
   `fn', except that a `'c'' is appended to the name.  For
   example, if `fn' is set to `init.sl', then the new file
   will have the name exmp{init.slc}.  The meaning of the second
   parameter, `reserved', is reserved for future use.  For now, set
   it to `0'.
   
   The function returns zero upon success, or `-1' upon error and
   sets SLang_Error accordingly.

 SEE ALSO
   SLang_load_file, SLang_init_slang
--------------------------------------------------------------

SLang_autoload

 SYNOPSIS
   Autoload a function from a file

 USAGE
   int SLang_autoload(char *funct, char *filename)

 DESCRIPTION
   The `SLang_autoload' function may be used to associate a
   `slang' function name `funct' with the file `filename'
   such that if `funct' has not already been defined when needed,
   it will be loaded from `filename'.
   
   `SLang_autoload' has no effect if `funct' has already been
   defined.  Otherwise it declares `funct' as a user-defined S-Lang
   function.  It returns `0' upon success, or `-1' upon error.

 SEE ALSO
   SLang_load_file, SLang_is_defined
--------------------------------------------------------------

SLang_load_string

 SYNOPSIS
   Interpret a string

 USAGE
   int SLang_load_string(char *str)

 DESCRIPTION
   The `SLang_load_string' function feeds the string specified by
   `str' to the interpreter for execution.  It returns zero upon
   success, or `-1' upon failure.

 SEE ALSO
   SLang_load_file, SLang_load_object
--------------------------------------------------------------

SLdo_pop

 SYNOPSIS
   Delete an object from the stack

 USAGE
   int SLdo_pop(void)

 DESCRIPTION
   This function removes an object from the top of the interpeter's
   run-time stack and frees any memory associated with it.  It returns
   zero upon success, or `-1' upon error (most likely due to a
   stack-underflow).

 SEE ALSO
   SLdo_pop_n, SLang_pop_integer, SLang_pop_string
--------------------------------------------------------------

SLdo_pop_n

 SYNOPSIS
   Delete n objects from the stack

 USAGE
   int SLdo_pop_n (unsigned int n)

 DESCRIPTION
   The `SLdo_pop_n' function removes the top `n' objects from
   the interpreter's run-time stack and frees all memory associated
   with the objects.  It returns zero upon success, or `-1' upon
   error (most likely due to a stack-underflow).

 SEE ALSO
   SLdo_pop, SLang_pop_integer, SLang_pop_string
--------------------------------------------------------------

SLang_pop_integer

 SYNOPSIS
   Pop an integer off the stack

 USAGE
   int SLang_pop_integer (int *i)

 DESCRIPTION
   The `SLang_pop_integer' function removes an integer from the
   top of the interpreter's run-time stack and returns its value via
   the pointer `i'.  If successful, it returns zero.  However, if
   the top stack item is not of type `SLANG_INT_TYPE', or the
   stack is empty, the function will return `-1' and set
   `SLang_Error' accordingly.

 SEE ALSO
   SLang_push_integer, SLang_pop_double
--------------------------------------------------------------

SLpop_string

 SYNOPSIS
   Pop a string from the stack

 USAGE
   int SLpop_string (char **strptr);

 DESCRIPTION
   The `SLpop_string' function pops a string from the stack and
   returns it as a malloced pointer.  It is up to the calling routine
   to free this string via a call to `free' or `SLfree'.  If
   successful, `SLpop_string' returns zero.  However, if the top
   stack item is not of type `SLANG_STRING_TYPE', or the stack is
   empty, the function will return `-1' and set
   `SLang_Error' accordingly.

 EXAMPLE

         define print_string (void)
         {
            char *s;
   	 if (-1 == SLpop_string (&s))
   	   return;
   	 fputs (s, stdout);
   	 SLfree (s);
         }


 NOTES
   This function should not be confused with `SLang_pop_slstring',
   which pops a _hashed_ string from the stack.

 SEE ALSO
   SLang_pop_slstring. SLfree
--------------------------------------------------------------

SLang_pop_string

 SYNOPSIS
   Pop a string from the stack

 USAGE
   int SLang_pop_string(char **strptr, int *do_free)

 DESCRIPTION
   The `SLpop_string' function pops a string from the stack and
   returns it as a malloced pointer via `strptr'.  After the
   function returns, the integer pointed to by the second parameter
   will be set to a non-zero value if `*strptr' should be freed via 
   `free' or `SLfree'.  If successful, `SLpop_string'
   returns zero.  However, if the top stack item is not of type
   `SLANG_STRING_TYPE', or the stack is empty, the function will
   return `-1' and set `SLang_Error' accordingly.

 NOTES
   This function is considered obsolete and should not be used by
   applications.  If one requires a malloced string for modification,
   `SLpop_string' should be used.  If one requires a constant
   string that will not be modifed by the application,
   `SLang_pop_slstring' should be used.

 SEE ALSO
   SLang_pop_slstring, SLpop_string
--------------------------------------------------------------

SLang_pop_slstring

 SYNOPSIS
   Pop a hashed string from the stack

 USAGE
   int SLang_pop_slstring (char **s_ptr)

 DESCRIPTION
   The `SLang_pop_slstring' function pops a hashed string from the
   S-Lang run-time stack and returns it via `s_ptr'.  It returns
   zero if successful, or -1 upon failure.  The resulting string
   should be freed via a call to `SLang_free_slstring' after use.

 EXAMPLE

      void print_string (void)
      {
         char *s;
         if (-1 == SLang_pop_slstring (&s))
           return;
         fprintf (stdout, "%s\n", s);
         SLang_free_slstring (s);
      }


 NOTES
   `SLang_free_slstring' is the preferred function for popping
   strings.  This is a result of the fact that the interpreter uses
   hashed strings as the native representation for string data.
   
   One must _never_ free a hashed string using `free' or
   `SLfree'.  In addition, one must never make any attempt to
   modify a hashed string and doing so will result in memory
   corruption.

 SEE ALSO
   SLang_free_slstring, SLpop_string
--------------------------------------------------------------

SLang_pop_double

 SYNOPSIS
   Pop a double from the stack

 USAGE
   int SLang_pop_double (double *dptr, int *iptr, int *conv)

 DESCRIPTION
   The `SLang_pop_double' function pops a double precision number
   from the stack and returns it via `dptr'.  If the number was
   derived from an integer, `*conv' will be set to `1' upon
   return, otherwise, `*conv' will be set to `0'.  This
   function returns 0 upon success, otherwise it returns -1 and sets
   `SLang_Error' accordingly.

 NOTES
   If one does not care whether or not `*dptr' was derived from
   an integer, `iptr' and `conv' may be passed as `NULL'
   pointers.

 SEE ALSO
   SLang_pop_integer, SLang_push_double
--------------------------------------------------------------

SLang_pop_complex

 SYNOPSIS
   Pop a complex number from the stack

 USAGE
   int SLang_pop_complex (double *re, double *im)

 DESCRIPTION
   `SLang_pop_complex' pops a complex number from the stack and
   returns it via the parameters `re' and `im' as the real and
   imaginary parts of the complex number, respectively.  This function
   automatically converts objects of type `SLANG_DOUBLE_TYPE' and
   `SLANG_INT_TYPE' to `SLANG_COMPLEX_TYPE', if necessary.
   It returns zero upon success, or -1 upon error setting
   `SLang_Error' accordingly.

 SEE ALSO
   SLang_pop_integer, SLang_pop_double, SLang_push_complex
--------------------------------------------------------------

SLang_push_complex

 SYNOPSIS
   Push a complex number onto the stack

 USAGE
   int SLang_push_complex (double re, double im)

 DESCRIPTION
   `SLang_push_complex' may be used to push the complex number
   whose real and imaginary parts are given by `re' and `im',
   respectively.  It returns zero upon success, or -1 upon error
   setting `SLang_Error' accordingly.

 SEE ALSO
   SLang_pop_complex, SLang_push_double
--------------------------------------------------------------

SLang_push_double

 SYNOPSIS
   Push a double onto the stack

 USAGE
   int SLang_push_double(double d)

 DESCRIPTION
   `SLang_push_double' may be used to push the double precision
   floating point number `d' onto the interpreter's run-time
   stack.  It returns zero upon success, or -1 upon error setting
   `SLang_Error' accordingly.

 SEE ALSO
   SLang_pop_double, SLang_push_integer
--------------------------------------------------------------

SLang_push_string

 SYNOPSIS
   Push a string onto the stack

 USAGE
   int SLang_push_string (char *s)

 DESCRIPTION
   `SLang_push_string' pushes a copy of the string specified by
   `s' onto the interpreter's run-time stack.  It returns zero
   upon success, or -1 upon error setting `SLang_Error'
   accordingly.

 NOTES
   If `s' is `NULL', this function pushes `NULL'
   (`SLANG_NULL_TYPE') onto the stack.

 SEE ALSO
   SLang_push_malloced_string
--------------------------------------------------------------

SLang_push_integer

 SYNOPSIS
   Push an integer onto the stack

 USAGE
   int SLang_push_integer (int i)

 DESCRIPTION
   `SLang_push_integer' the integer `i' onto the interpreter's
   run-time stack.  It returns zero upon success, or -1 upon error
   setting `SLang_Error' accordingly.

 SEE ALSO
   SLang_pop_integer, SLang_push_double, SLang_push_string
--------------------------------------------------------------

SLang_push_malloced_string

 SYNOPSIS
   Push a malloced string onto the stack

 USAGE
   int SLang_push_malloced_string (char *s);

 DESCRIPTION
   `SLang_push_malloced_string' may be used to push a malloced
   string onto the interpreter's run-time stack.  It returns zero upon
   success, or -1 upon error setting `SLang_Error' accordingly.

 EXAMPLE
   The following example illustrates that it is up to the calling
   routine to free the string if `SLang_push_malloced_string' fails:

         int push_hello (void)
         {
            char *s = malloc (6);
   	 if (s == NULL) return -1;
   	 strcpy (s, "hello");
   	 if (-1 == SLang_push_malloced_string (s))
   	   {
   	      free (s);
   	      return -1;
   	   }
   	 return 0;
         }


 EXAMPLE
   The function `SLang_create_slstring' returns a hashed string.
   Such a string may not be malloced and should not be passed to
   `SLang_push_malloced_string'.

 NOTES
   If `s' is `NULL', this function pushes `NULL'
   (`SLANG_NULL_TYPE') onto the stack.

 SEE ALSO
   SLang_push_string, SLmake_string
--------------------------------------------------------------

SLang_is_defined

 SYNOPSIS
   Check to see if the interpreter defines an object

 USAGE
   int SLang_is_defined (char *nm)

 DESCRIPTION
   The `SLang_is_defined' function may be used to determine
   whether or not a variable or function whose name is given by
   `em' has been defined.  It returns zero if no such object has
   been defined.  Othewise it returns a non-zero value whose meaning
   is given by the following table:

         1    intrinsic function  (SLANG_INTRINSIC)
         2    user-defined slang function (SLANG_FUNCTION)
        -1    intrinsic variable (SLANG_IVARIABLE)
        -2    user-defined global variable (SLANG_GVARIABLE)


 SEE ALSO
   SLadd_intrinsic_function, SLang_run_hooks, SLang_execute_function
--------------------------------------------------------------

SLang_run_hooks

 SYNOPSIS
   Run a user-defined hook with arguments

 USAGE
   int SLang_run_hooks (char *fname, unsigned int n, ...)

 DESCRIPTION
   The `SLang_run_hooks' function may be used to execute a
   user-defined function named `fname'.  Before execution of the
   function, the `n' string arguments specified by the variable
   parameter list are pushed onto the stack.  If the function
   `fname' does not exist, `SLang_run_hooks' returns zero;
   otherwise, it returns `1' upon successful execution of the
   function, or -1 if an error occurred.

 EXAMPLE
   The jed editor uses `SLang_run_hooks' to setup the mode of a
   buffer based on the filename extension of the file associated with
   the buffer:

         char *ext = get_filename_extension (filename);
         if (ext == NULL) return -1;
         if (-1 == SLang_run_hooks ("mode_hook", 1, ext))
           return -1;
         return 0;


 SEE ALSO
   SLang_is_defined, SLang_execute_function
--------------------------------------------------------------

SLang_execute_function

 SYNOPSIS
   Execute a user or intrinsic function

 USAGE
   int SLang_execute_function (char *fname)

 DESCRIPTION
   This function may be used to execute either a user-defined function
   or an intrinisic function.  The name of the function is specified
   by `fname'.  It returns zero if `fname' is not defined, or
   `1' if the function was successfully executed, or -1 upon
   error.

 NOTES
   The function `SLexecute_function' may be a better alternative
   for some uses.

 SEE ALSO
   SLang_run_hooks, SLexecute_function, SLang_is_defined
--------------------------------------------------------------

SLang_verror

 SYNOPSIS
   Signal an error with a message

 USAGE
   void SLang_verror (int code, char *fmt, ...);

 DESCRIPTION
   The `SLang_verror' function sets `SLang_Error' to
   `code' if `SLang_Error' is 0.  It also displays the error
   message implied by the `printf' variable argument list using
   `fmt' as the format.

 EXAMPLE

         FILE *open_file (char *file)
         {
            char *file = "my_file.dat";
   	 if (NULL == (fp = fopen (file, "w")))
   	   SLang_verror (SL_INTRINSIC_ERROR, "Unable to open %s", file);
   	 return fp;
         }


 SEE ALSO
   SLang_vmessage, SLang_exit_error
--------------------------------------------------------------

SLang_doerror

 SYNOPSIS
   Signal an error

 USAGE
   void SLang_doerror (char *err_str)

 DESCRIPTION
   The `SLang_doerror' function displays the string `err_str'
   to the error device and signals a S-Lang error.

 NOTES
   `SLang_doerror' is considered to obsolete.  Applications should
   use the `SLang_verror' function instead.

 SEE ALSO
   SLang_verror, SLang_exit_error
--------------------------------------------------------------

SLang_get_function

 SYNOPSIS
   Get a pointer to a slang function

 USAGE
   SLang_Name_Type *SLang_get_function (char *fname)

 DESCRIPTION
   This function returns a pointer to the internal S-Lang table entry
   of a function whose name is given by `fname'.  It returns
   `NULL' upon failure.  The value returned by this function can be
   used `SLexecute_function' to call the function directly
   from C.

 SEE ALSO
   SLexecute_function
--------------------------------------------------------------

SLexecute_function

 SYNOPSIS
   Execute a slang or intrinsic function

 USAGE
   int SLexecute_function (SLang_Name_Type *nt)

 DESCRIPTION
   The `SLexecute_function' allows an application to call the
   S-Lang function specified by the `SLang_Name_Type' pointer
   `nt'.  This parameter must be non `NULL' and must have been
   previously obtained by a call to `SLang_get_function'.

 EXAMPLE
   Consider the S-Lang function:

        define my_fun (x)
        {
           return x^2 - 2;
        }

   Suppose that it is desired to call this function many times with
   different values of x.  There are at least two ways to do this.
   The easiest way is to use `SLang_execute_function' by passing
   the string `"my_fun"'.  A better way that is much faster is to
   use `SLexecute_function':

         int sum_a_function (char *fname, double *result)
         {
            double sum, x, y;
   	 SLang_Name_Type *nt;
   
   	 if (NULL == (nt = SLang_get_function (fname)))
   	   return -1;
   	 
   	 sum = 0;
   	 for (x = 0; x < 10.0; x += 0.1)
   	   {
   	      SLang_start_arg_list ();
   	      if (-1 == SLang_push_double (x))
   	        return -1;
   	      SLang_end_arg_list ();
   	      if (-1 == SLexecute_function (nt))
   	        return -1;
   	      if (-1 == SLang_pop_double (&y, NULL, NULL))
   	        return -1;
   	      
   	      sum += y;
   	   }
   	 return sum;
         }

   Although not necessary in this case, `SLang_start_arg_list' and
   `SLang_end_arg_list' were used to provide the function with
   information about the number of parameters passed to it.

 SEE ALSO
   SLang_get_function, SLang_start_arg_list, SLang_end_arg_list
--------------------------------------------------------------

SLang_peek_at_stack

 SYNOPSIS
   Find the type of object on the top of the stack

 USAGE
   int SLang_peek_at_stack (void)

 DESCRIPTION
   The `SLang_peek_at_stack' function is useful for determining the
   data type of the object at the top of the stack.  It returns the
   data type, or -1 upon a stack-underflow error.  It does not remove
   anything from the stack.

 SEE ALSO
   SLang_pop_string, SLang_pop_integer
--------------------------------------------------------------

SLmake_string

 SYNOPSIS
   Duplicate a string

 USAGE
   char *SLmake_string (char *s)

 DESCRIPTION
   The `SLmake_string' function creates a new copy of the string
   `s', via `malloc', and returns it.  Upon failure it returns
   `NULL'.  Since the resulting string is malloced, it should be
   freed when nolonger needed via a call to either `free' or
   `SLfree'.

 NOTES
   `SLmake_string' should not be confused with the function
   `SLang_create_slstring', which performs a similar function.

 SEE ALSO
   SLmake_nstring, SLfree, SLmalloc, SLang_create_slstring
--------------------------------------------------------------

SLmake_nstring

 SYNOPSIS
   Duplicate a substring

 USAGE
   char *SLmake_nstring (char *s, unsigned int n)

 DESCRIPTION
   This function is like `SLmake_nstring' except that it creates a
   null terminated string formed from the first `n' characters of
   `s'.  Upon failure, it returns `NULL', otherwise it returns
   the new string.  When nolonger needed, the returned string should be
   freed with either `free' or `SLfree'.

 SEE ALSO
   SLmake_nstring, SLfree, SLang_create_nslstring
--------------------------------------------------------------

SLang_create_nslstring

 SYNOPSIS
   Created a hashed substring

 USAGE
   char *SLang_create_nslstring (char *s, unsigned int n)

 DESCRIPTION
   `SLang_create_nslstring' is like `SLang_create_slstring'
   except that only the first `n' characters of `s' are used to
   perform the string.  Upon error, it returns `NULL', otherwise it
   returns the hashed substring.  Such a string must be freed by the
   function `SLang_free_slstring'.

 NOTES
   Do not use `free' or `SLfree' to free the string returned by
   `SLang_create_slstring' or `SLang_create_nslstring'.  Also
   it is important that no attempt is made to modify the hashed string
   returned by either of these functions.  If one needs to modify a
   string, the functions `SLmake_string' or `SLmake_nstring'
   should be used instead.

 SEE ALSO
   SLang_free_slstring, SLang_create_slstring, SLmake_nstring
--------------------------------------------------------------

SLang_create_slstring

 SYNOPSIS
   Create a hashed string

 USAGE
   char *SLang_create_slstring (char *s)

 DESCRIPTION
   The `SLang_create_slstring' creates a copy of `s' and
   returns it as a hashed string.  Upon error, the function returns
   `NULL', otherwise it returns the hashed string.  Such a string
   must only be freed via the `SLang_free_slstring' function.

 NOTES
   Do not use `free' or `SLfree' to free the string returned by
   `SLang_create_slstring' or `SLang_create_nslstring'.  Also
   it is important that no attempt is made to modify the hashed string
   returned by either of these functions.  If one needs to modify a
   string, the functions `SLmake_string' or `SLmake_nstring'
   should be used instead.

 SEE ALSO
   SLang_free_slstring, SLang_create_nslstring, SLmake_string
--------------------------------------------------------------

SLang_free_slstring

 SYNOPSIS
   Free a hashed string

 USAGE
   void SLang_free_slstring (char *s)

 DESCRIPTION
   The `SLang_free_slstring' function is used to free a hashed
   string such as one returned by `SLang_create_slstring',
   `SLang_create_nslstring', or `SLang_create_static_slstring'.
   If `s' is `NULL', the routine does nothing.

 SEE ALSO
   SLang_create_slstring, SLang_create_nslstring, SLang_create_static_slstring
--------------------------------------------------------------

SLang_concat_slstrings

 SYNOPSIS
   Concatenate two strings to produce a hashed string

 USAGE
   char *SLang_concat_slstrings (char *a, char *b)

 DESCRIPTION
   The `SLang_concat_slstrings' function concatenates two strings,
   `a' and `b', and returns the result as a hashed string.
   Upon failure, `NULL' is returned.

 NOTES
   A hashed string can only be freed using `SLang_free_slstring'.
   Never use either `free' or `SLfree' to free a hashed string,
   otherwise memory corruption will result.

 SEE ALSO
   SLang_free_slstring, SLang_create_slstring
--------------------------------------------------------------

SLang_create_static_slstring

 SYNOPSIS
   Create a hashed string

 USAGE
   char *SLang_create_static_slstring (char *s_literal)

 DESCRIPTION
   The `SLang_create_static_slstring' creates a hashed string from
   the string literal `s_literal' and returns the result.  Upon
   failure it returns `NULL'.

 EXAMPLE

        char *create_hello (void)
        {
           return SLang_create_static_slstring ("hello");
        }


 NOTES
   This function should only be used with string literals.

 SEE ALSO
   SLang_create_slstring, SLang_create_nslstring
--------------------------------------------------------------

SLmalloc

 SYNOPSIS
   Allocate some memory

 USAGE
   char *SLmalloc (unsigned int nbytes)

 DESCRIPTION
   This function uses `malloc' to allocate `nbytes' of memory.
   Upon error it returns `NULL'; otherwise it returns a pointer to
   the allocated memory.  One should use `SLfree' to free the
   memory after used.

 SEE ALSO
   SLfree, SLrealloc, SLcalloc
--------------------------------------------------------------

SLcalloc

 SYNOPSIS
   Allocate some memory

 USAGE
   char *SLcalloc (unsigned int num_elem, unsigned int elem_size)

 DESCRIPTION
   This function uses `calloc' to allocate memory for
   `num_elem' objects with each of size `elem_size' and returns
   the result.  In addition, the newly allocated memory is zeroed. 
   Upon error it returns `NULL'; otherwise it returns a pointer to
   the allocated memory.  One should use `SLfree' to free the
   memory after used.

 SEE ALSO
   SLmalloc, SLrealloc, SLfree
--------------------------------------------------------------

SLfree

 SYNOPSIS
   Free some allocated memory

 USAGE
   void SLfree (char *ptr)

 DESCRIPTION
   The `SLfree' function uses `free' to deallocate the memory
   specified by `ptr', which may be `NULL' in which case the
   function does nothing.

 NOTES
   Never use this function to free a hashed string returned by one of
   the family of `slstring' functions, e.g.,
   `SLang_pop_slstring'.

 SEE ALSO
   SLmalloc, SLcalloc, SLrealloc, SLmake_string
--------------------------------------------------------------

SLrealloc

 SYNOPSIS
   Resize a dynamic memory block

 USAGE
   char *SLrealloc (char *ptr, unsigned int new_size)

 DESCRIPTION
   The `SLrealloc' uses the `realloc' function to resize the
   memory block specified by `ptr' to the new size `new_size'.
   If `ptr' is `NULL', the function call is equivalent to
   `SLmalloc(new_size)'.  Similarly, if `new_size' is zero,
   the function call is equivalent to `SLfree(ptr)'.  
   
   If the function fails, or if `new_size' is zero, `NULL' is
   returned.  Otherwise a pointer is returned to the (possibly moved)
   new block of memory.

 SEE ALSO
   SLfree, SLmalloc, SLcalloc
--------------------------------------------------------------

SLcurrent_time_string

 SYNOPSIS
   Get the current time as a string

 USAGE
   char *SLcurrent_time_string (void)

 DESCRIPTION
   The `SLcurrent_time_string' function uses the C library function
   `ctime' to obtain a string representation of the
   current date and time in the form

        "Wed Dec 10 12:50:28 1997"

   However, unlike the `ctime' function, a newline character is not
   present in the string.  
   
   The returned value points to a statically allocated memory block
   which may get overwritten on subsequent function calls.

 SEE ALSO
   SLmake_string
--------------------------------------------------------------

SLatoi

 SYNOPSIS
   Convert a text string to an integer

 USAGE
   int SLatoi(unsigned char *str

 DESCRIPTION
   `SLatoi' parses the string `str' to interpret it as an
   integer value.  Unlike `atoi', `SLatoi' can also parse
   strings containing integers expressed in
   hexidecimal (e.g., `"0x7F"') and octal (e.g., `"012"'.)
   notation.

 SEE ALSO
   SLang_guess_type
--------------------------------------------------------------

SLang_pop_fileptr

 SYNOPSIS
   Pop a file pointer

 USAGE
   int SLang_pop_fileptr (SLang_MMT_Type **mmt, FILE **fp)

 DESCRIPTION
   `SLang_pop_fileptr' pops a file pointer from the S-Lang
   run-time stack.  It returns zero upon success, or -1 upon failure.
   
   A S-Lang file pointer (SLANG_FILEPTR_TYPE) is actually a memory
   managed object.  For this reason, `SLang_pop_fileptr' also
   returns the memory managed object via the argument list.  It is up
   to the calling routine to call `SLang_free_mmt' to free the
   object.

 EXAMPLE
   The following example illustrates an application defined intrinsic
   function that writes a user defined double precision number to a
   file.  Note the use of `SLang_free_mmt':

        int write_double (void)
        {
           double t;
   	SLang_MMT_Type *mmt;
   	FILE *fp;
   	int status;
   
   	if (-1 == SLang_pop_double (&d, NULL, NULL))
   	  return -1;
   	if (-1 == SLang_pop_fileptr (&mmt, &fp))
   	  return -1;
   	
   	status = fwrite (&d, sizeof (double), 1, fp);
   	SLang_free_mmt (mmt);
           return status;
        }

   This function can be used by a S-Lang function as follows:

        define write_some_values ()
        {
           variable fp, d;
   
   	fp = fopen ("myfile.dat", "wb");
   	if (fp == NULL)
   	  error ("file failed to open");
   	for (d = 0; d < 10.0; d += 0.1)
   	  {
   	     if (-1 == write_double (fp, d))
   	       error ("write failed");
   	  }
   	if (-1 == fclose (fp))
   	  error ("fclose failed");
        }


 SEE ALSO
   SLang_free_mmt, SLang_pop_double
--------------------------------------------------------------

SLadd_intrinsic_function

 SYNOPSIS
   Add a new intrinsic function to the interpreter

 USAGE
   int SLadd_intrinsic_function (name, f, type, nargs, ...)

       char *name
       FVOID_STAR f
       unsigned char type
       unsigned int nargs


 DESCRIPTION
   The `SLadd_intrinsic_function' function may be used to add a new
   intrinsic function.  The S-Lang name of the function is specified by
   `name' and the actual function pointer is given by `f', cast
   to `FVOID_STAR'.  The third parameter, `type' specifies the
   return type of the function and must be one of the following values:

       SLANG_VOID_TYPE   (returns nothing)
       SLANG_INT_TYPE    (returns int)
       SLANG_DOUBLE_TYPE (returns double)
       SLANG_STRING_TYPE (returns char *)

   The `nargs' parameter specifies the number of parameters to pass
   to the function.  The variable argument list following `nargs'
   must consists of `nargs' integers which specify the data type of
   each argument.
   
   The function returns zero upon success or -1 upon failure.

 EXAMPLE
   The jed editor uses this function to change the `system'
   intrinsic function to the following:

        static int jed_system (char *cmd)
        {
           if (Jed_Secure_Mode)
   	  {
   	    msg_error ("Access denied.");
   	    return -1;
   	  }	  
   	return SLsystem (cmd);
        }

   After initializing the interpreter with `SLang_init_slang',
   jed calls `SLadd_intrinsic_function' to substitute the above
   definition for the default S-Lang definition:

        if (-1 == SLadd_intrinsic_function ("system", (FVOID_STAR)jed_system,
                                             SLANG_INT_TYPE, 1,
   					  SLANG_STRING_TYPE))
          return -1;


 SEE ALSO
   SLadd_intrinsic_variable, SLadd_intrinsic_array
--------------------------------------------------------------

SLadd_intrinsic_variable

 SYNOPSIS
   Add an intrinsic variable to the interpreter

 USAGE
   int SLadd_intrinsic_variable (name, addr, type, rdonly)

       char *name
       VOID_STAR type
       unsigned char type
       int rdonly


 DESCRIPTION
   The `SLadd_intrinsic_variable' function adds an intrinsic
   variable called `name' to the interpeter.  The second parameter
   `addr' specifies the address of the variable (cast to
   `VOID_STAR').  The third parameter, `type', specifies the
   data type of the variable.  If the fourth parameter, `rdonly',
   is non-zero, the variable will interpreted by the interpreter as
   read-only.
   
   If successful, `SLadd_intrinsic_variable' returns zero,
   otherwise it returns -1.

 EXAMPLE
   Suppose that `My_Global_Int' is a global variable (at least not
   a local one):

       int My_Global_Int;

   It can be added to the interpreter via the function call

       if (-1 == SLadd_intrinsic_variable ("MyGlobalInt",
                                           (VOID_STAR)&My_Global_Int,
   					SLANG_INT_TYPE, 0))
         exit (1);


 NOTES
   The current implementation requires all pointer type intrinsic
   variables to be read-only.  For example,

       char *My_Global_String;

   is of type `SLANG_STRING_TYPE', and must be declared as
   read-only.  Finally, not that

      char My_Global_Char_Buf[256];

   is _not_ a `SLANG_STRING_TYPE' object.  This difference is
   very important because internally the interpreter dereferences the
   address passed to it to get to the value of the variable.

 SEE ALSO
   SLadd_intrinsic_function, SLadd_intrinsic_array
--------------------------------------------------------------

SLclass_add_unary_op

 SYNOPSIS
   ??

 USAGE
   int SLclass_add_unary_op (unsigned char,int (*) (int, unsigned char, VOID_STAR, unsigned int, VOID_STAR), int (*) (int, unsigned char, unsigned char *));

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLclass_add_app_unary_op

 SYNOPSIS
   ??

 USAGE
   int SLclass_add_app_unary_op (unsigned char, int (*) (int,unsigned char, VOID_STAR, unsigned int,VOID_STAR),int (*) (int, unsigned char, unsigned char *));

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLclass_add_binary_op

 SYNOPSIS
   ??

 USAGE
   int SLclass_add_binary_op (unsigned char, unsigned char,int (*)(int, unsigned char, VOID_STAR, unsigned int,unsigned char, VOID_STAR, unsigned int,VOID_STAR),int (*) (int, unsigned char, unsigned char, unsigned char *));

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLclass_add_math_op

 SYNOPSIS
   ??

 USAGE
   int SLclass_add_math_op (unsigned char,int (*)(int,unsigned char, VOID_STAR, unsigned int,VOID_STAR),int (*)(int, unsigned char, unsigned char *));

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLclass_add_typecast

 SYNOPSIS
   ??

 USAGE
   int SLclass_add_typecast (unsigned char, unsigned char int (*)_PROTO((unsigned char, VOID_STAR, unsigned int,unsigned char, VOID_STAR)),int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLang_init_tty

 SYNOPSIS
   Initialize the terminal keyboard interface

 USAGE
   int SLang_init_tty (int intr_ch, int no_flow_ctrl, int opost)

 DESCRIPTION
   `SLang_init_tty' initializes the terminal for single character
   input.  If the first parameter `intr_ch' is in the range 0-255,
   it will be used as the interrupt character, e.g., under Unix this
   character will generate a `SIGINT' signal.  Otherwise, if it is
   `-1', the interrupt character will be left unchanged.  
   
   If the second parameter `no_flow_ctrl' is non-zero, flow control
   (`XON'/`XOFF') processing will be
   enabled.  
   
   If the last parmeter `opost' is non-zero, output processing by the
   terminal will be enabled.  If one intends to use this function in
   conjunction with the S-Lang screen management routines
   (`SLsmg'), this paramete shold be set to zero.
   
   `SLang_init_tty' returns zero upon success, or -1 upon error.

 NOTES
   Terminal I/O is a complex subject.  The S-Lang interface presents a
   simplification that the author has found useful in practice.  For
   example, the only special character processing that
   `SLang_init_tty' enables is that of the `SIGINT' character,
   and the generation of other signals via the keyboard is disabled.
   However, generation of the job control signal `SIGTSTP' is possible
   via the `SLtty_set_suspend_state' function.
   
   Under Unix, the integer variable `SLang_TT_Read_FD' is used to
   specify the input descriptor for the terminal.  If
   `SLang_TT_Read_FD' represents a terminal device as determined
   via the `isatty' system call, then it will be used as the
   terminal file descriptor.  Otherwise, the terminal device
   `/dev/tty' will used as the input device.  The default value of
   `SLang_TT_Read_FD' is -1 which causes `/dev/tty' to be
   used.  So, if you prefer to use `stdin' for input, then set
   `SLang_TT_Read_FD' to `fileno(stdin)' _before_ calling
   `SLang_init_tty'.
   
   If the variable `SLang_TT_Baud_Rate' is zero when this function
   is called, the function will attempt to determine the baud rate by
   querying the terminal driver and set `SLang_TT_Baud_Rate' to
   that value.  

 SEE ALSO
   SLang_reset_tty, SLang_getkey, SLtty_set_suspend_state
--------------------------------------------------------------

SLang_reset_tty

 SYNOPSIS
   Reset the terminal

 USAGE
   void SLang_reset_tty (void)

 DESCRIPTION
   `SLang_reset_tty' resets the terminal interface back to the
   state it was in before `SLang_init_tty' was called.

 SEE ALSO
   SLang_init_tty
--------------------------------------------------------------

SLtty_set_suspend_state

 SYNOPSIS
   Enable or disable keyboard suspension

 USAGE
   void SLtty_set_suspend_state (int s)

 DESCRIPTION
   The `SLtty_set_suspend_state' function may be used to enable or
   disable keyboard generation of the `SIGTSTP' job control signal.
   If `s' is non-zero, generation of this signal via the terminal
   interface will be enabled, otherwise it will be disabled.
   
   This function should only be called after the terminal driver has be
   initialized via `SLang_init_tty'.  The `SLang_init_tty'
   always disables the generation of `SIGTSTP' via the keyboard.

 SEE ALSO
   SLang_init_tty
--------------------------------------------------------------

SLang_getkey

 SYNOPSIS
   Read a character from the keyboard

 USAGE
   unsigned int SLang_getkey (void);

 DESCRIPTION
   The `SLang_getkey' reads a single character from the terminal
   and returns it.  The terminal must first be initialized via a call
   to `SLang_init_tty' before this function can be called.  Upon
   success, `SLang_getkey' returns the character read from the
   terminal, otherwise it returns `SLANG_GETKEY_ERROR'.

 SEE ALSO
   SLang_init_tty, SLang_input_pending, SLang_ungetkey
--------------------------------------------------------------

SLang_ungetkey_string

 SYNOPSIS
   Unget a key string

 USAGE
   int SLang_ungetkey_string (unsigned char *buf, unsigned int n)

 DESCRIPTION
   The `SLang_ungetkey_string' function may be used to push the
   `n' characters pointed to by `buf' onto the buffered input
   stream that `SLgetkey' uses.  If there is not enough room for
   the characters, -1 is returned and none are buffered.  Otherwise,
   it returns zero.

 NOTES
   The difference between `SLang_buffer_keystring' and
   `SLang_ungetkey_string' is that the `SLang_buffer_keystring'
   appends the characters to the end of the getkey buffer, whereas
   `SLang_ungetkey_string' inserts the characters at the beginning
   of the input buffer.

 SEE ALSO
   SLang_ungetkey, SLang_getkey
--------------------------------------------------------------

SLang_buffer_keystring

 SYNOPSIS
   Append a keystring to the input buffer

 USAGE
   int SLang_buffer_keystring (unsigned char *b, unsigned int len)

 DESCRIPTION
   `SLang_buffer_keystring' places the `len' characters
   specified by `b' at the _end_ of the buffer that
   `SLang_getkey' uses.  Upon success it returns 0; otherwise, no
   characters are buffered and it returns -1.

 NOTES
   The difference between `SLang_buffer_keystring' and
   `SLang_ungetkey_string' is that the `SLang_buffer_keystring'
   appends the characters to the end of the getkey buffer, whereas
   `SLang_ungetkey_string' inserts the characters at the beginning
   of the input buffer.

 SEE ALSO
   SLang_getkey, SLang_ungetkey, SLang_ungetkey_string
--------------------------------------------------------------

SLang_ungetkey

 SYNOPSIS
   Push a character back onto the input buffer

 USAGE
   int SLang_ungetkey (unsigned char ch)

 DESCRIPTION
   `SLang_ungetkey' pushes the character `ch' back onto the
   `SLgetkey' input stream.  Upon success, it returns zero,
   otherwise it returns 1.

 EXAMPLE
   This function is implemented as:

       int SLang_ungetkey (unsigned char ch)
       {
          return SLang_ungetkey_string(&ch, 1);
       }


 SEE ALSO
   SLang_getkey, SLang_ungetkey_string
--------------------------------------------------------------

SLang_flush_input

 SYNOPSIS
   Discard all keyboard input waiting to be read

 USAGE
   void SLang_flush_input (void)

 DESCRIPTION
   `SLang_flush_input' discards all input characters waiting to be
   read by the `SLang_getkey' function.

 SEE ALSO
   SLang_getkey
--------------------------------------------------------------

SLang_input_pending

 SYNOPSIS
   Check to see if input is pending

 USAGE
   int SLang_input_pending (int tsecs)

 DESCRIPTION
   `SLang_input_pending' may be used to see if an input character
   is available to be read without causing `SLang_getkey' to block.
   It will wait up to `tsecs' tenths of a second if no characters
   are immediately available for reading.  If `tsecs' is less than
   zero, then `SLang_input_pending' will wait `-tsecs'
   milliseconds for input, otherwise `tsecs' represents `1/10'
   of a second intervals.

 NOTES
   Not all systems support millisecond resolution.

 SEE ALSO
   SLang_getkey
--------------------------------------------------------------

SLang_set_abort_signal

 SYNOPSIS
   Set the signal to trap SIGINT

 USAGE
   void SLang_set_abort_signal (void (*f)(int));

 DESCRIPTION
   `SLang_set_abort_signal' sets the function that gets
   triggered when the user presses the interrupt key (`SIGINT') to
   the function `f'.  If `f' is `NULL' the default handler
   will get installed.

 EXAMPLE
   The default interrupt handler on a Unix system is:

        static void default_sigint (int sig)
        {
           SLKeyBoard_Quit = 1;
   	if (SLang_Ignore_User_Abort == 0) SLang_Error = SL_USER_BREAK;
   	SLsignal_intr (SIGINT, default_sigint);
      }


 NOTES
   For Unix programmers, the name of this function may appear
   misleading since it is associated with `SIGINT' and not
   `SIGABRT'.  The origin of the name stems from the original intent
   of the function: to allow the user to abort the running of a S-Lang
   interpreter function.

 SEE ALSO
   SLang_init_tty, SLsignal_intr
--------------------------------------------------------------

SLkm_define_key

 SYNOPSIS
   Define a key in a keymap

 USAGE
   int SLkm_define_key (char *seq, FVOID_STAR f, SLKeyMap_List_Type *km)

 DESCRIPTION
   `SLkm_define_key' associates the key sequence `seq' with the
   function pointer `f' in the keymap specified by `km'.  Upon
   success, it returns zero, otherwise it returns a negative integer
   upon error.

 SEE ALSO
   SLkm_define_keysym, SLang_define_key
--------------------------------------------------------------

SLang_define_key

 SYNOPSIS
   Define a key in a keymap

 USAGE
   int SLang_define_key(char *seq, char *fun, SLKeyMap_List_Type *km)

 DESCRIPTION
   `SLang_define_key' associates the key sequence `seq' with
   the function whose name is `fun' in the keymap specified by
   `km'.

 SEE ALSO
   SLkm_define_keysym, SLkm_define_key
--------------------------------------------------------------

SLkm_define_keysym

 SYNOPSIS
   Define a keysym in a keymap

 USAGE
   int SLkm_define_keysym (seq, ks, km)

         char *seq;
         unsigned int ks;
         SLKeyMap_List_Type *km;


 DESCRIPTION
   `SLkm_define_keysym' associates the key sequence `seq' with
   the keysym `ks' in the keymap `km'.  Keysyms whose value is
   less than or equal to `0x1000' is reserved by the library and
   should not be used.

 SEE ALSO
   SLkm_define_key, SLang_define_key
--------------------------------------------------------------

SLang_undefine_key

 SYNOPSIS
   Undefined a key from a keymap

 USAGE
   void SLang_undefine_key(char *seq, SLKeyMap_List_Type *km);

 DESCRIPTION
   `SLang_undefine_key' removes the key sequence `seq' from the
   keymap `km'.

 SEE ALSO
   SLang_define_key
--------------------------------------------------------------

SLang_create_keymap

 SYNOPSIS
   Create a new keymap

 USAGE
   SLKeyMap_List_Type *SLang_create_keymap (name, km)

        char *name;
        SLKeyMap_List_Type *km;


 DESCRIPTION
   `SLang_create_keymap' creates a new keymap called `name' by
   copying the key definitions from the keymap `km'.  If `km'
   is `NULL', the newly created keymap will be empty and it is up
   to the calling routine to initialize it via the
   `SLang_define_key' and `SLkm_define_keysym' functions.
   `SLang_create_keymap' returns a pointer to the new keymap, or
   `NULL' upon failure.

 SEE ALSO
   SLang_define_key, SLkm_define_keysym
--------------------------------------------------------------

SLang_do_key

 SYNOPSIS
   Read a keysequence and return its keymap entry

 USAGE
   SLang_Key_Type *SLang_do_key (kml, getkey)

        SLKeyMap_List_Type *kml;
        int (*getkey)(void);


 DESCRIPTION
   The `SLang_do_key' function reads characters using the function
   specified by the `getkey' function pointer and uses the
   key sequence to return the appropriate entry in the keymap specified
   by `kml'.
   
   `SLang_do_key' returns `NULL' if the key sequence is not
   defined by the keymap, otherwise it returns a pointer to an object
   of type `SLang_Key_Type', which is defined in `slang.h' as

        #define SLANG_MAX_KEYMAP_KEY_SEQ 14
        typedef struct SLang_Key_Type
        {
          struct SLang_Key_Type *next;
          union
          {
             char *s;
   	  FVOID_STAR f;
   	  unsigned int keysym;
          }
          f;
          unsigned char type;	       /* type of function */
        #define SLKEY_F_INTERPRET  0x01
        #define SLKEY_F_INTRINSIC  0x02
        #define SLKEY_F_KEYSYM     0x03
          unsigned char str[SLANG_MAX_KEYMAP_KEY_SEQ + 1];/* key sequence */
        }
   SLang_Key_Type;
   

   The `type' field specifies which field of the union `f'
   should be used.  If `type' is `SLKEY_F_INTERPRET', then
   `f.s' is a string that should be passed to the interpreter for
   evaluation.  If `type' is `SLKEY_F_INTRINSIC', then
   `f.f' refers to function that should be called.  Otherwise,
   `type' is `SLKEY_F_KEYSYM' and `f.keysym' represents the
   value of the keysym that is associated with the key sequence.

 SEE ALSO
   SLkm_define_keysym, SLkm_define_key
--------------------------------------------------------------

SLang_find_key_function

 SYNOPSIS
   Obtain a function pointer associated with a keymap

 USAGE
   FVOID_STAR SLang_find_key_function (fname, km);

       char *fname;
       SLKeyMap_List_Type *km;


 DESCRIPTION
   The `SLang_find_key_function' routine searches through the
   `SLKeymap_Function_Type' list of functions associated with the
   keymap `km' for the function with name `fname'.
   If a matching function is found, a pointer to the function will
   be returned, otherwise `SLang_find_key_function' will return
   `NULL'.

 SEE ALSO
   SLang_create_keymap, SLang_find_keymap
--------------------------------------------------------------

SLang_find_keymap

 SYNOPSIS
   Find a keymap

 USAGE
   SLKeyMap_List_Type *SLang_find_keymap (char *keymap_name);

 DESCRIPTION
   The `SLang_find_keymap' function searches through the list of
   keymaps looking for one whose name is `keymap_name'.  If a
   matching keymap is found, the function returns a pointer to the
   keymap.  It returns `NULL' if no such keymap exists.

 SEE ALSO
   SLang_create_keymap, SLang_find_key_function
--------------------------------------------------------------

SLang_process_keystring

 SYNOPSIS
   Un-escape a key-sequence

 USAGE
   char *SLang_process_keystring (char *kseq);

 DESCRIPTION
   The `SLang_process_keystring' function converts an escaped key
   sequence to its raw form by converting two-character combinations
   such as `^A' to the _single_ character `Ctrl-A' (ASCII
   1).  In addition, if the key sequence contains constructs such as
   `^(XX)', where `XX' represents a two-character termcap
   specifier, the termcap escape sequence will be looked up and
   substituted.   
   
   Upon success, `SLang_process_keystring' returns a raw
   key-sequence whose first character represents the total length of
   the key-sequence, including the length specifier itself.  It returns
   `NULL' upon failure.

 EXAMPLE
   Consider the following examples:

        SLang_process_keystring ("^X^C");
        SLang_process_keystring ("^[[A");

   The first example will return a pointer to a buffer of three characters
   whose ASCII values are given by `{3,24,3}'.  Similarly, the
   second example will return a pointer to the four characters
   `{4,27,91,65}'.  Finally, the result of

        SLang_process_keystring ("^[^(ku)");

   will depend upon the termcap/terminfo capability `"ku"', which
   represents the escape sequence associated with the terminal's UP
   arrow key.  For an ANSI terminal whose UP arrow produces
   `"ESC [ A"', the result will be `5,27,27,91,65'.

 NOTES
   `SLang_process_keystring' returns a pointer to a static area
   that will be overwritten on subsequent calls.

 SEE ALSO
   SLang_define_key, SLang_make_keystring
--------------------------------------------------------------

SLang_make_keystring

 SYNOPSIS
   Make a printable key sequence

 USAGE
   char *SLang_make_keystring (unsigned char *ks);

 DESCRIPTION
   The `SLang_make_keystring' function takes a raw key sequence
   `ks' and converts it to a printable form by converting
   characters such as ASCII 1 (ctrl-A) to `^A'.  That is, it
   performs the opposite function of `SLang_process_keystring'.

 NOTES
   This function returns a pointer to a static area that will be
   overwritten on the next call to `SLang_make_keystring'.

 SEE ALSO
   SLang_process_keystring
--------------------------------------------------------------

SLextract_list_element

 SYNOPSIS
   Extract a substring of a delimited string

 USAGE
   int SLextract_list_element (dlist, nth, delim, buf, buflen)

       char *dlist;
       unsigned int nth;
       char delim;
       char *buf;
       unsigned int buflen;


 DESCRIPTION
   `SLextract_list_element' may be used to obtain the `nth'
   element of a list of strings, `dlist', that are delimited by the
   character `delim'.  The routine copies the `nth' element of
   `dlist' to the buffer `buf' whose size is `buflen'
   characters.  It returns zero upon success, or -1 if `dlist'
   does not contain an `nth' element.

 EXAMPLE
   A delimited list of strings may be turned into an array of strings
   as follows.  For conciseness, all malloc error checking has been
   omitted.

       int list_to_array (char *list, char delim, char ***ap)
       {
          unsigned int nth;
          char **a;
          char buf[1024];
   
          /* Determine the size of the array */
          nth = 0;
          while (0 == SLextract_list_element (list, nth, delim, buf, sizeof(buf)))
            nth++;
          
          ap = (char **) SLmalloc ((nth + 1) * sizeof (char **));
          nth = 0;
          while (0 == SLextract_list_element (list, nth, delim, buf, sizeof(buf)))
            {
   	     a[nth] = SLmake_string (buf);
   	     nth++;
   	 }
          a[nth] = NULL;
          *ap = a;
          return 0;
       }


 SEE ALSO
   SLmalloc, SLmake_string
--------------------------------------------------------------

SLprep_open_prep

 SYNOPSIS
   ??

 USAGE
   int SLprep_open_prep (SLPreprocess_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLprep_close_prep

 SYNOPSIS
   ??

 USAGE
   void SLprep_close_prep (SLPreprocess_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLprep_line_ok

 SYNOPSIS
   ??

 USAGE
   int SLprep_line_ok (char *, SLPreprocess_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLdefine_for_ifdef

 SYNOPSIS
   ??

 USAGE
   int SLdefine_for_ifdef (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLang_Read_Line_Type * SLang_rline_save_line (SLang_RLine_Info_Type *);

 SYNOPSIS
   ??

 USAGE
   SLang_Read_Line_Type * SLang_rline_save_line (SLang_RLine_Info_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLang_init_readline (SLang_RLine_Info_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLang_init_readline (SLang_RLine_Info_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLang_read_line (SLang_RLine_Info_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLang_read_line (SLang_RLine_Info_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLang_rline_insert (char *);

 SYNOPSIS
   ??

 USAGE
   int SLang_rline_insert (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLrline_redraw (SLang_RLine_Info_Type *);

 SYNOPSIS
   ??

 USAGE
   void SLrline_redraw (SLang_RLine_Info_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_flush_output (void);

 SYNOPSIS
   ??

 USAGE
   int SLtt_flush_output (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_scroll_region(int, int);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_scroll_region(int, int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_reset_scroll_region(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_reset_scroll_region(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_reverse_video (int);

 SYNOPSIS
   ??

 USAGE
   void SLtt_reverse_video (int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_bold_video (void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_bold_video (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_begin_insert(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_begin_insert(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_end_insert(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_end_insert(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_del_eol(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_del_eol(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_goto_rc (int, int);

 SYNOPSIS
   ??

 USAGE
   void SLtt_goto_rc (int, int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_delete_nlines(int);

 SYNOPSIS
   ??

 USAGE
   void SLtt_delete_nlines(int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_delete_char(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_delete_char(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_erase_line(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_erase_line(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_normal_video(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_normal_video(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_cls(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_cls(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_beep(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_beep(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_reverse_index(int);

 SYNOPSIS
   ??

 USAGE
   void SLtt_reverse_index(int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_smart_puts(unsigned short *, unsigned short *, int, int);

 SYNOPSIS
   ??

 USAGE
   void SLtt_smart_puts(unsigned short *, unsigned short *, int, int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_write_string (char *);

 SYNOPSIS
   ??

 USAGE
   void SLtt_write_string (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_putchar(char);

 SYNOPSIS
   ??

 USAGE
   void SLtt_putchar(char);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_init_video (void);

 SYNOPSIS
   ??

 USAGE
   int SLtt_init_video (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_reset_video (void);

 SYNOPSIS
   ??

 USAGE
   int SLtt_reset_video (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_get_terminfo(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_get_terminfo(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_get_screen_size (void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_get_screen_size (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_set_cursor_visibility (int);

 SYNOPSIS
   ??

 USAGE
   int SLtt_set_cursor_visibility (int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_initialize (char *);

 SYNOPSIS
   ??

 USAGE
   int SLtt_initialize (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_enable_cursor_keys(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_enable_cursor_keys(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_term_vtxxx(int *);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_term_vtxxx(int *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_color_esc (int, char *);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_color_esc (int, char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_wide_width(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_wide_width(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_narrow_width(void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_narrow_width(void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_set_mouse_mode (int, int);

 SYNOPSIS
   ??

 USAGE
   int SLtt_set_mouse_mode (int, int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_alt_char_set (int);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_alt_char_set (int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_write_to_status_line (char *, int);

 SYNOPSIS
   ??

 USAGE
   int SLtt_write_to_status_line (char *, int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_disable_status_line (void);

 SYNOPSIS
   ??

 USAGE
   void SLtt_disable_status_line (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLtt_tgetstr (char *);

 SYNOPSIS
   ??

 USAGE
   char *SLtt_tgetstr (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_tgetnum (char *);

 SYNOPSIS
   ??

 USAGE
   int SLtt_tgetnum (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_tgetflag (char *);

 SYNOPSIS
   ??

 USAGE
   int SLtt_tgetflag (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLtt_tigetent (char *);

 SYNOPSIS
   ??

 USAGE
   char *SLtt_tigetent (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLtt_tigetstr (char *, char **);

 SYNOPSIS
   ??

 USAGE
   char *SLtt_tigetstr (char *, char **);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLtt_tigetnum (char *, char **);

 SYNOPSIS
   ??

 USAGE
   int SLtt_tigetnum (char *, char **);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLtt_Char_Type SLtt_get_color_object (int);

 SYNOPSIS
   ??

 USAGE
   SLtt_Char_Type SLtt_get_color_object (int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_color_object (int, SLtt_Char_Type);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_color_object (int, SLtt_Char_Type);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_color (int, char *, char *, char *);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_color (int, char *, char *, char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_mono (int, char *, SLtt_Char_Type);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_mono (int, char *, SLtt_Char_Type);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_add_color_attribute (int, SLtt_Char_Type);

 SYNOPSIS
   ??

 USAGE
   void SLtt_add_color_attribute (int, SLtt_Char_Type);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLtt_set_color_fgbg (int, SLtt_Char_Type, SLtt_Char_Type);

 SYNOPSIS
   ??

 USAGE
   void SLtt_set_color_fgbg (int, SLtt_Char_Type, SLtt_Char_Type);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLkp_define_keysym (char *, unsigned int);

 SYNOPSIS
   ??

 USAGE
   int SLkp_define_keysym (char *, unsigned int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLkp_init (void);

 SYNOPSIS
   ??

 USAGE
   int SLkp_init (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLkp_getkey (void);

 SYNOPSIS
   ??

 USAGE
   int SLkp_getkey (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLscroll_find_top (SLscroll_Window_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLscroll_find_top (SLscroll_Window_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLscroll_find_line_num (SLscroll_Window_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLscroll_find_line_num (SLscroll_Window_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

unsigned int SLscroll_next_n (SLscroll_Window_Type *, unsigned int);

 SYNOPSIS
   ??

 USAGE
   unsigned int SLscroll_next_n (SLscroll_Window_Type *, unsigned int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

unsigned int SLscroll_prev_n (SLscroll_Window_Type *, unsigned int);

 SYNOPSIS
   ??

 USAGE
   unsigned int SLscroll_prev_n (SLscroll_Window_Type *, unsigned int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLscroll_pageup (SLscroll_Window_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLscroll_pageup (SLscroll_Window_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLscroll_pagedown (SLscroll_Window_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLscroll_pagedown (SLscroll_Window_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLSig_Fun_Type *SLsignal (int, SLSig_Fun_Type *);

 SYNOPSIS
   ??

 USAGE
   SLSig_Fun_Type *SLsignal (int, SLSig_Fun_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

SLSig_Fun_Type *SLsignal_intr (int, SLSig_Fun_Type *);

 SYNOPSIS
   ??

 USAGE
   SLSig_Fun_Type *SLsignal_intr (int, SLSig_Fun_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLsig_block_signals (void);

 SYNOPSIS
   ??

 USAGE
   int SLsig_block_signals (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLsig_unblock_signals (void);

 SYNOPSIS
   ??

 USAGE
   int SLsig_unblock_signals (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLsystem (char *);

 SYNOPSIS
   ??

 USAGE
   int SLsystem (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLadd_at_handler (long *, char *);

 SYNOPSIS
   ??

 USAGE
   void SLadd_at_handler (long *, char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLang_define_case(int *, int *);

 SYNOPSIS
   ??

 USAGE
   void SLang_define_case(int *, int *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLang_init_case_tables (void);

 SYNOPSIS
   ??

 USAGE
   void SLang_init_case_tables (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

unsigned char *SLang_regexp_match(unsigned char *, unsigned int, SLRegexp_Type *);

 SYNOPSIS
   ??

 USAGE
   unsigned char *SLang_regexp_match(unsigned char *, unsigned int, SLRegexp_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLang_regexp_compile (SLRegexp_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLang_regexp_compile (SLRegexp_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLregexp_quote_string (char *, char *, unsigned int);

 SYNOPSIS
   ??

 USAGE
   char *SLregexp_quote_string (char *, char *, unsigned int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLcmd_execute_string (char *, SLcmd_Cmd_Table_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLcmd_execute_string (char *, SLcmd_Cmd_Table_Type *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLsearch_init (char *, int, int, SLsearch_Type *);

 SYNOPSIS
   ??

 USAGE
   int SLsearch_init (char *, int, int, SLsearch_Type *);

 DESCRIPTION
   ??
   /* This routine must first be called before any search can take place.
   * The second parameter specifies the direction of the search: greater than
   * zero for a forwrd search and less than zero for a backward search.  The
   * third parameter specifies whether the search is case sensitive or not.
   * The last parameter is a pointer to a structure that is filled by this
   * function and it is this structure that must be passed to SLsearch.
   */

 SEE ALSO
   ??
--------------------------------------------------------------

unsigned char *SLsearch (unsigned char *, unsigned char *, SLsearch_Type *);

 SYNOPSIS
   ??

 USAGE
   unsigned char *SLsearch (unsigned char *, unsigned char *, SLsearch_Type *);

 DESCRIPTION
   ??
   /* To use this routine, you must first call 'SLsearch_init'.  Then the first
   * two parameters p1 and p2 serve to define the region over which the search
   * is to take place.  The third parameter is the structure that was previously
   * initialized by SLsearch_init.
   *
   * The routine returns a pointer to the match if found otherwise it returns
   * NULL.
   */

 SEE ALSO
   ??
--------------------------------------------------------------

SLcomplex_abs

 SYNOPSIS
   Returns the norm of a complex number

 USAGE
   double SLcomplex_abs (double *z)

 DESCRIPTION
   The `SLcomplex_abs' function returns the absolute value or the
   norm of the complex number given by `z'.

 SEE ALSO
   SLcomplex_times
--------------------------------------------------------------

double *SLcomplex_times (double *, double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_times (double *, double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_divide (double *, double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_divide (double *, double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_sin (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_sin (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_cos (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_cos (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_tan (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_tan (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_asin (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_asin (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_acos (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_acos (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_atan (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_atan (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_exp (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_exp (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_log (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_log (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_log10 (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_log10 (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_sqrt (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_sqrt (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_sinh (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_sinh (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_cosh (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_cosh (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_tanh (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_tanh (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_pow (double *, double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_pow (double *, double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double SLmath_hypot (double x, double y);

 SYNOPSIS
   ??

 USAGE
   double SLmath_hypot (double x, double y);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_acosh (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_acosh (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

double *SLcomplex_atanh (double *, double *);

 SYNOPSIS
   ??

 USAGE
   double *SLcomplex_atanh (double *, double *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLdebug_malloc (unsigned long);

 SYNOPSIS
   ??

 USAGE
   char *SLdebug_malloc (unsigned long);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLdebug_calloc (unsigned long, unsigned long);

 SYNOPSIS
   ??

 USAGE
   char *SLdebug_calloc (unsigned long, unsigned long);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLdebug_realloc (char *, unsigned long);

 SYNOPSIS
   ??

 USAGE
   char *SLdebug_realloc (char *, unsigned long);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLdebug_free (char *);

 SYNOPSIS
   ??

 USAGE
   void SLdebug_free (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLmalloc_dump_statistics (void);

 SYNOPSIS
   ??

 USAGE
   void SLmalloc_dump_statistics (void);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLstrcpy(register char *, register char *);

 SYNOPSIS
   ??

 USAGE
   char *SLstrcpy(register char *, register char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLstrcmp(register char *, register char *);

 SYNOPSIS
   ??

 USAGE
   int SLstrcmp(register char *, register char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

char *SLstrncpy(char *, register char *, register  int);

 SYNOPSIS
   ??

 USAGE
   char *SLstrncpy(char *, register char *, register  int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLmemset (char *, char, int);

 SYNOPSIS
   ??

 USAGE
   void SLmemset (char *, char, int);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLexpand_escaped_string (register char *, register char *, register char *);

 SYNOPSIS
   ??

 USAGE
   void SLexpand_escaped_string (register char *, register char *, register char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

void SLmake_lut (unsigned char *, unsigned char *, unsigned char);

 SYNOPSIS
   ??

 USAGE
   void SLmake_lut (unsigned char *, unsigned char *, unsigned char);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

int SLang_guess_type (char *);

 SYNOPSIS
   ??

 USAGE
   int SLang_guess_type (char *);

 DESCRIPTION
   ??

 SEE ALSO
   ??
--------------------------------------------------------------

