STATFS(2)

NAME
statfs, fstatfs - get file system statistics

SYNOPSIS
#include <sys/param.h>
#include <sys/mount.h>
int
statfs(const char *path, struct statfs *buf);
int
fstatfs(int fd, struct statfs *buf);

DESCRIPTION
statfs() returns information about a mounted file system. path is the path name of any file within the mounted file system. buf is a pointer to a statfs structure defined as follows:

    typedef struct { int32_t val[2]; } fsid_t;
    #define MFSNAMELEN   16 /* length of fs type name, including nul */
    #define MNAMELEN     90	/* length of buffer for returned name */
    struct statfs {
       u_int32_t       f_flags;        /* copy of mount flags */
       u_int32_t       f_bsize;        /* file system block size */
       u_int32_t       f_iosize;       /* optimal transfer block size */
                                       /* unit is f_bsize */
       u_int64_t       f_blocks;       /* total data blocks in file system */
       u_int64_t       f_bfree;        /* free blocks in fs */
       int64_t         f_bavail;       /* free blocks avail to non-superuser */
       u_int64_t       f_files;        /* total file nodes in file system */
       u_int64_t       f_ffree;        /* free file nodes in fs */
       int64_t         f_favail;       /* free file nodes avail to non-root */
       u_int64_t       f_syncwrites;   /* count of sync writes since mount */
       u_int64_t       f_syncreads;    /* count of sync reads since mount */
       u_int64_t       f_asyncwrites;  /* count of async writes since mount */
       u_int64_t       f_asyncreads;   /* count of async reads since mount */
       fsid_t          f_fsid;         /* file system id */
       u_int32_t       f_namemax;      /* maximum filename length */
       uid_t           f_owner;        /* user that mounted the file system */
       u_int64_t       f_ctime;        /* last mount [-u] time */
       char f_fstypename[MFSNAMELEN];  /* fs type name */
       char f_mntonname[MNAMELEN];     /* directory on which mounted */
       char f_mntfromname[MNAMELEN];   /* mounted file system */
       char f_mntfromspec[MNAMELEN];   /* special for mount request */
       union mount_info mount_info;    /* per-filesystem mount options */
    };

fstatfs() returns the same information about an open file referenced by descriptor fd.

Note that f_fsid will be empty unless the user is the superuser.

RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS
statfs() fails if one or more of the following are true:

[ENOTDIR]
    A component of the path prefix of path is not a directory.

[ENAMETOOLONG]
    The length of a component of path exceeds {NAME_MAX} characters, or the length of path exceeds {PATH_MAX} characters.

[ENOENT]
    The file referred to by path does not exist.

[EACCES]
    Search permission is denied for a component of the path prefix of path.

[ELOOP]
    Too many symbolic links were encountered in translating path.

[EFAULT]
    buf or path points to an invalid address.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

fstatfs() fails if one or more of the following are true:

[EBADF]
    fd is not a valid open file descriptor.

[EFAULT]
    buf points to an invalid address.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

SEE ALSO
df(1), getfsstat(2), mount(2), stat(2)

HISTORY
The statfs() function first appeared in 4.4BSD.