umount(2) — AIX PS/2 1.2.1



UMOUNT(2,L)                 AIX Technical Reference                 UMOUNT(2,L)



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umount, fumount



PURPOSE

Unmounts a file system.

SYNTAX



                int umount (dev)            int fumount  (dev)
                char *dev;                  char *dev;



DESCRIPTION

The umount and fumount system calls unmount a previously mounted file system
contained on the block device (also called a special file) identified by the
dev parameter.  The dev parameter is a pointer to a path name.

The umount system call does not unmount a file system if it contains open
files.  The fumount system call forces the file system to be unmounted even if
it contains open files.  The open files are closed by the system before
unmounting and the file system is left in a clean state, ready for re-mounting.
However, a file system is never unmounted if another file system is mounted on
it.

If the Transparent Computing Facility is installed and the file system is
replicated, the local copy may be unmounted if there are other copies of the
file system still mounted.

After the file system is unmounted, the directory upon which the file system
was mounted reverts to its ordinary interpretation as a directory.

The umount and fumount system calls can be invoked only by a process whose
effective user ID is superuser.

RETURN VALUE

Upon successful completion, a value of 0 is returned.  If the umount or fumount
system call fails, a value of -1 is returned and errno is set to indicate the
error.

ERROR CONDITIONS

The umount or fumount system call fails if one or more of the following are
true:




Processed November 7, 1990        UMOUNT(2,L)                                 1



UMOUNT(2,L)                 AIX Technical Reference                 UMOUNT(2,L)



EPERM     The process's effective user ID is not superuser.

ENOENT    dev does not exist.

ENOTBLK   dev is not the name of a block special file.

EINVAL    dev is not mounted.

EINVAL    dev is not local.

EBUSY     A file on the device specified by the dev parameter is currently in
          use.

EFAULT    dev points to a location outside of the process's allocated address
          space.

ENXIO     dev is not currently configured.

ENAMETOOLONG
          A component of the dev parameter exceeded NAME_MAX characters or the
          entire dev parameter exceeded PATH_MAX characters.

ENOENT    A symbolic link was named, but the file to which it refers does not
          exist.

ELOOP     A loop of symbolic links was detected.

If the Transparent Computing Facility is installed on your system, umount or
fumount can also fail if one or more of the following are true:

ENOSTORE  dev is a name relative to the working directory, but no site which
          stores this directory is currently up.

ENOSTORE  A component of dev is replicated but not stored on any site which is
          currently up.

EINTR     A signal was caught during the system call.

RELATED INFORMATION

In this book:  "mount."

The mount and umount commands in AIX Operating System Commands Reference.












Processed November 7, 1990        UMOUNT(2,L)                                 2

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