STATFS(2-SysV)      RISC/os Reference Manual       STATFS(2-SysV)



NAME
     statfs, fstatfs - get file system information

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

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

     int fstatfs (fildes, buf, len, fstyp)
     int fildes;
     struct statfs *buf;
     int len, 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
     can 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.  Read, write, or exe-
     cute permission of the named file is not required, but all
     directories listed in the path name leading to the file must
     be searchable.

     For either mounted or unmounted file systems, path can name
     the block special file for the partition containing the file
     system. In this case, the fstype argument must be set to the
     correct file system type.

     The statfs structure pointed to by buf includes the follow-
     ing 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*/



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          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 */

     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.

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

     [ENOTDIR]   A component of the path prefix is not a direc-
                 tory.

     [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).

     [ENOLINK]   path points to a remote machine, and the link to
                 that machine is no longer active.

     [EMULTIHOP] Components of path require hopping to multiple
                 remote machines.

ANOMALIES
     The f_bfree field of the returned data structure returns a
     number which is consistent with a BSD filesystem.  In other
     words, zero free blocks really means 90% of the filesystem
     is filled.  If any more space is used, the number of free
     blocks will actually go negative.  We chose these semantics
     because reporting free blocks as a function of the total
     disk space would result in an inability for users to write
     to a 90% full filesystem.

DIAGNOSTICS
     Upon successful completion a value of 0 is returned.



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     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), time(2), unlink(2), utime(2), write(2), fs.ffs(4).

















































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