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umount(2)			 System	Calls			     umount(2)

       umount, umount2 - unmount a file	system

       #include	<sys/mount.h>

       int umount(const	char *file);

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

       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 interpreta-

       The umount2()  function is identical to umount(), with  the  additional
       capability  of unmounting file systems even if there are	open files ac-
       tive. 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	unsuc-
		       cessful.	The umount2() function	returns	ENOTSUP	if the
		       specified  file systems does not	support	MS_FORCE. Cur-
		       rently only nfs-	 and  ufs-type	file  systems  support

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

       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

			       The  mountpoint	is not a regular file or a di-
			       rectory and the caller does not have all	privi-
			       leges 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 ille-
			       gal 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

       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 ma-
			       chine and the link to that machine is no	longer

       ENOTBLK		       The file	pointed	to by file is not a block spe-
			       cial 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.

       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

       mount(2), privileges(5)

SunOS 5.10			  22 Mar 2004			     umount(2)


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