umount(2)                                                            umount(2)


NAME
     umount - unmount a file system

C 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 a process with the super-user privilege.

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

     EPERM               The calling process does not have the super-user
                         privilege.

     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 {PATH_MAX},
                         or the length of a file component exceeds {NAME_MAX}
                         while _POSIX_NO_TRUNC is in effect.

     ENOTDIR             file does not point to a directory.

     ENOENT              A component ofthe path prefix does not exist or is a
                         null pathname.

     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                         machine is no longer active.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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