umount(2)
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umount System Call
Remove a file system device.
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SYNTAX
#include <sys/mount.h>
int umount (special)
char * special;
PARAMETERS
special Address of a pathname.
DESCRIPTION
Umount removes the file system device identified by <special> or
mounted on the directory <special> from the set of active file
system devices with the following consequences:
* The filename store contained on <special> is removed from
the system filename store. Thus, all files contained on
<special> can no longer be named.
* The filesystem contained on <special> is removed from the
system flat file store. Thus, all files contained on
<special> can no longer be accessed.
* None of the files on <special> may be open. No process may
have its current working directory on <special>.
* The filename store contained on <special> cannot contain a
mount point of any other file system device at the time of
the call to umount.
* <Special> must have previously been the subject of a
successful mount operation. If umount is successful, the
sub-tree over which <special> was mounted reappears in the
system file name store. These files can now be named.
If an error occurs, no changes are made.
ACCESS CONTROL
The calling process's effective user id must be the superuser.
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umount(2)
RETURN VALUE
0 <Special> was successfully unmounted.
-1 An error occurred. Errno is set to indicate the
error.
EXCEPTIONS
Errno may be set to one of the following error codes:
EBUSY The channel store of <special> is not empty.
EBUSY A file contained on <special> is the graft point
of another file system device.
EINVAL <Special> is not mounted.
ENOENT The named file does not exist.
ENOTBLK <Special> is not a block special file.
ENXIO The device associated with <special> does not
exist.
EIO I/O error on flushing superblock.
EPERM Permission to unmount the file system device is
denied to the calling process.
ENOENT A non-terminal component of the pathname does not
exist.
ENOTDIR A non-terminal component of the pathname was not a
directory or symbolic link.
ENAMETOOLONG The pathname exceeds the length limit for
pathnames.
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umount(2)
ENAMETOOLONG A component of the pathname exceeds the length
limit for filenames.
ENOMEM There are not enough system resources to resolve
the pathname or to expand a symbolic link.
ELOOP The number of symbolic links encountered during
pathname resolution exceeded MAXSYMLINKS. A
symbolic link cycle is suspected.
EPERM The pathname contains a character not in the
allowed character set.
EFAULT The pathname does not completely reside in the
process's address space or the pathname does not
terminate in the process's address space.
SEE ALSO
The related manual sections: mount(2), nfsmount(2)
fs(4).
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