GIMP Library Reference Manual
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# gimpsignal

## Name

gimpsignal -- Portable signal handling.

## Synopsis

    #define     SA_RESTART
    void        (*GimpSignalHandlerFunc)        (gint signum);
    GimpSignalHandlerFunc gimp_signal_private   (gint signum,
                                                 GimpSignalHandlerFunc handler,
                                                 gint flags);
    #define     gimp_signal_syscallrestart      (signum,handler)

## Description

Portable signal handling.

## Details

### SA_RESTART

    #define SA_RESTART SA_SYSV

This is just an alias for systems which do not define SA_RESTART.

### GimpSignalHandlerFunc ()

    void        (*GimpSignalHandlerFunc)        (gint signum);

A prototype for signal handler functions. Note that each function which takes or returns a variable of this type also accepts or may return special values defined by your system's signal.h header file (like `SIG_DFL` or `SIG_IGN`).

`signum` : | The number of the signal. Useful if different signals are handled by a single handler.

### gimp_signal_private ()

    GimpSignalHandlerFunc gimp_signal_private   (gint signum,
                                                 GimpSignalHandlerFunc handler,
                                                 gint flags);

This function furnishes a workalike for signal(2) but which internally invokes sigaction(2) after certain sa_flags are set; these primarily to ensure restarting of interrupted system calls. See sigaction(2) It is a aid to transition and not new development: that effort should employ sigaction directly. [gosgood 18.04.2000]

Cause `handler` to be run when `signum` is delivered. We use sigaction(2) rather than signal(2) so that we can control the signal handler's environment completely via `flags`: some signal(2) implementations differ in their sematics, so we need to nail down exactly what we want. [austin 06.04.2000]

`signum` : | Selects signal to be handled see man 5 signal (or man 7 signal)
`handler` : | Handler that maps to signum. Invoked by O/S. Handler gets signal that caused invocation. Corresponds to the `sa_handler` field of the `sigaction` struct.
`flags` : | Preferences. OR'ed SA_<xxx>. See man sigaction. Corresponds to the `sa_flags` field of the `sigaction` struct.
Returns : | A reference to the signal handling function which was active before the call to gimp_signal_private().

### gimp_signal_syscallrestart()

    #define gimp_signal_syscallrestart(signum,handler) gimp_signal_private ((signum), (handler), SA_RESTART)

Installs a signal handler in a way that system calls which were not finished at the time of signal handler invocation will be silently restarted by the system (without failing with an error of EINTR).

`signum` : | The number of the signal.
`handler` : | The signal handler.

## See Also

signal(2), signal(5 or 7), sigaction(2).

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