umount(2)                        UNIX System V                        umount(2)


NAME
      umount - unmount a file system

SYNOPSIS
      #include <sys/mount.h>

      int umount(const char *file);

DESCRIPTION
      umount requests that a previously mounted file system contained on the
      block special device or directory identified by file be unmounted.  file
      is a pointer to a path name.  After unmounting the file system, the
      directory upon which the file system was mounted reverts to its ordinary
      interpretation.

      umount may be invoked only by the super-user.

      umount will fail if one or more of the following are true:

      EPERM               The process's effective user ID is not super-user.

      EINVAL              file does not exist.

      ELOOP               Too many symbolic links were encountered in
                          translating the path pointed to by file.

      ENAMETOOLONG        The length of the file argument exceeds {PATHMAX},
                          or the length of a file component exceeds {NAMEMAX}
                          while POSIXNOTRUNC is in effect.

      ENOTBLK             file is not a block special device.

      EINVAL              file is not mounted.

      EBUSY               A file on file is busy.

      EFAULT              file points to an illegal address.

      EREMOTE             file is remote.

      ENOLINK             file is on a remote machine, and the link to that
                          machine is no longer active.

      EMULTIHOP           Components of the path pointed to by file require
                          hopping to multiple remote machines.

SEE ALSO
      mount(2).

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.


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