umount(2)							   System Calls 							 umount(2)

NAME

       umount, umount2 - unmount a file system

SYNOPSIS

       #include <sys/mount.h>

       int umount(const char *file);

       int umount2(const char *file, int mflag);

DESCRIPTION

       The  umount()   function requests that a previously mounted file system contained on a block special device or directory be unmounted.  The
       file argument is a pointer to the absolute pathname of the file system to be unmounted. After unmounting the  file  system,  the  directory
       upon which the file system was mounted reverts to its ordinary interpretation.

       The  umount2()	function  is identical to umount(), with the additional capability of unmounting file systems even if there are open files
       active. The mflag argument must contain one of the following values:

       0	   Perform a normal unmount that is equivalent to umount(). The umount2() function  returns EBUSY if there are open  files  active
		   within the file system to be unmounted.

       MS_FORCE    Unmount the file system, even if there are open files active. A forced unmount can result in loss of data, so it should be used
		   only when a regular unmount is unsuccessful. The umount2() function	returns ENOTSUP if the specified  file	systems  does  not
		   support MS_FORCE. Only file systems of type nfs, ufs, pcfs, and zfs support MS_FORCE.

RETURN VALUES

       Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       The umount() and umount2() functions will fail if:

       EACCES	       The permission bits of the mount point do not permit read/write access or search permission is denied on a component of the
		       path prefix.

		       The calling process is not the owner of the mountpoint.

		       The mountpoint is not a regular file or a directory and the caller does not have all privileges available in a its zone.

		       The special device device does not permit read access in the case of read-only mounts or read-write access in the  case	of
		       read/write mounts.

       EBUSY	       A file on file is busy.

       EFAULT	       The file pointed to by file points to an illegal address.

       EINVAL	       The file pointed to by 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.

       ENOENT	       The file pointed to by file does not exist or is not an absolute path.

       ENOLINK	       The file pointed to by file is on a remote machine and the link to that machine is no longer active.

       ENOTBLK	       The file pointed to by file is not a block special device.

       EPERM	       The {PRIV_SYS_MOUNT} privilege is not asserted in the effective set of the calling process.

       EREMOTE	       The file pointed to by file is remote.

       The umount2() function will fail if:

       ENOTSUP	  The file pointed to by file does not support this operation.

USAGE

       The umount() and umount2() functions can be invoked only by a process that has the {PRIV_SYS_MOUNT} privilege  asserted	in  its  effective
       set.

       Because it provides greater functionality, the umount2() function is preferred.

SEE ALSO

       mount(2), privileges(5)

SunOS 5.11							    4 Aug 2008								 umount(2)