umount(2)

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 a process with the P_MOUNT privilege.

Return values

On success, umount returns 0. On failure, umount returns -1 and sets errno to identify the error.

In the following conditions, umount fails and sets errno to:

EBUSY: A file on file is busy.
EINVAL: file does not exist.
EINVAL: file is not mounted.
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 of the path prefix does not exist or is a null pathname.
ENOTBLK: file is not a block special device.
EPERM: The calling process does not have the P_MOUNT privilege.
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ENOLINK: file is on a remote machine, and the link to that machine is no longer active.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.

References

mount(2)

Notices

umount will now resolve the mount_point argument using realpath(3C) before any processing is performed.