STATFS(2)                                                            STATFS(2)


NAME
     statfs, fstatfs - get file system information

SYNOPSIS
     #include <sys/types.h>
     #include <sys/statfs.h>

     int statfs (const char *path, struct statfs *buf, int len, int fstyp);

     int fstatfs (int fildes, struct statfs *buf, int len, int fstyp);

DESCRIPTION
     statfs returns a ``generic superblock'' describing a file system.  It can
     be used to acquire information about mounted as well as unmounted file
     systems, and usage is slightly different in the two cases.  In all cases,
     buf is a pointer to a structure (described below) which will be filled by
     the system call, and len is the number of bytes of information which the
     system should return in the structure.  Len must be no greater than
     sizeof (struct statfs) and ordinarily it will contain exactly that value;
     if it holds a smaller value the system will fill the structure with that
     number of bytes.  (This allows future versions of the system to grow the
     structure without invalidating older binary programs.)

     If the file system of interest is currently mounted, path should name a
     file which resides on that file system.  In this case the file system
     type is known to the operating system and the fstyp argument must be
     zero.  For an unmounted file system path must name the block special file
     containing it and fstyp must contain the (non-zero) file system type.  In
     both cases read, write, or execute permission of the named file is not
     required, but all directories listed in the path name leading to the file
     must be searchable.

     The statfs structure pointed to by buf includes the following members:
          short   f_fstyp;    /* File system type */
          long    f_bsize;    /* Block size */
          long    f_frsize;   /* Fragment size */
          long    f_blocks;   /* Total number of blocks */
          long    f_bfree;    /* Count of free blocks */
          long    f_files;    /* Total number of file nodes */
          long    f_ffree;    /* Count of free file nodes */
          char    f_fname[6]; /* Volume name */
          char    f_fpack[6]; /* Pack name */

     In ABI N32 applications, the fields f_blocks, f_bfree, f_files, and
     f_ffree are of type __int64_t (long long) instead of long.

     fstatfs is similar, except that the file named by path in statfs is
     instead identified by an open file descriptor filedes obtained from a
     successful open(2), creat(2), dup(2), fcntl(2), or pipe(2) system call.


     statfs obsoletes ustat(2) and should be used in preference to it in new
     programs.

     For XFS filesystems with real-time subvolumes (see xfs(4)), the statfs(2)
     system call returns information concerning the data portion of the
     filesystem only.  The syssgi(2) system call with the SGI_XFS_OPERATIONS
     request argument can be used to acquire information concerning the size
     and usage of space within the real-time portion of the filesystem.

     statfs and fstatfs will fail if one or more of the following are true:

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

     [ENOENT]       The named file does not exist.

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

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

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

     [EINVAL]       Fstyp is an invalid file system type; path is not a block
                    special file and fstyp is nonzero; len is negative or is
                    greater than sizeof (struct statfs).

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

SEE ALSO
     chmod(2), chown(2), creat(2), link(2), mknod(2), pipe(2), read(2),
     statvfs(2), time(2), unlink(2), utime(2), write(2), fs(4).


                                                                        Page 2