UMOUNT(2)                            SysV                            UMOUNT(2)



NAME
     umount - unmount a file system

SYNOPSIS
     int umount (file)
     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 pathname.  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.

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

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

     [EINVAL]      file does not exist.

     [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.

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 as indicated under "Errors."

NOTES
     Under other implementations, umount fails if either of the following is
     true:

     [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                   no longer active.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.