umount

Purpose

     Unmounts a file system.

Syntax

     int umount (dev)
     char *dev;

Description

     The umount system call unmounts 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.

     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 system  call 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 system  call fails, a value of  -1 is returned
     and errno is set to indicate the error.

Diagnostics

     The umount system  call fails if one or more  of the fol-
     lowing are true:

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

     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 &pointsout..

     ENXIO      dev is not currently configured.

Related Information

     In this book:  "mount,"  "uvmount," and "vmount."

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