hpux man page for memcntl

memcntl(2)							System Calls Manual							memcntl(2)

NAME
       memcntl() - memory management control

SYNOPSIS
   Parameters
       addr	 A  multiple  of page size as returned by the routine where implemented; otherwise, addr must contain the value NULL.  Where used,
		 control operations can be further defined with the bit pattern contained in attr.

       len	 Must be for the and operations.

       cmd	 The operation to be performed.  See the subsection in for a list of the symbolic names used  for  the	operations,  as  they  are
		 defined in

       arg	 A bit pattern built from the flags used to control the behavior of the operation, where implemented; otherwise, arg must be

       attr	 The page attributes.  If an operation is not to be controlled by these attributes, the attr argument must be

       mask	 Must be Reserved for future use.

DESCRIPTION
       The function enables the calling process to exercise various control operations over the address space, which is identified by the mappings
       set for the address range (addr, addr+len).

   Selection Criteria
       The scope of the control operations can be further specified with additional selection criteria (in the form of	attributes)  according	to
       the bits contained in the attr parameter.

       To specify the selection criteria for page protection, use the following attributes:

       Page is readable.
		      When used, it provides mapped segments with read and execute permission.

       Page is writable.
		      When used, it provides mapped segments with read, write and execute permission.

       Page is executable.
		      When used, it provides mapped segments with read and execute permission.

       Additional criteria include the following:

       Process Text.  When  used,  it  provides  all privately mapped segments with read and execute permission.  This criterion is applicable for
		      Itanium(R)-based systems only.

       Process Data.  When used, it provides all privately mapped segments with read and write permissions.

       The selection criteria are constructed by an OR of the attribute bits and must match exactly.   The  selection  criteria  can  be  used	to
       describe many abstract memory objects with the address space on which to operate.

   Operations
       The following are the symbolic names for operations as defined in
       Lock  in  memory  all  pages  in the range with attributes defined by the attr parameter.  Although a specified page may be locked multiple
       times through different mappings, page locks do not nest within a specified mapping.

	      A single unlock operation removes multiple lock operations that occur on a page with the same address in the  same  process.   If  a
	      page  is	locked	in  one  process,  but	mapped in another, or visible through a different mapping in the locking process, the lock
	      remains in memory until the locking process completes an either implicit or explicit unlock operation.

	      Removing a locked mapping or deleting a page through file removal or truncation causes an implicit unlock operation.  However, if  a
	      writable page in the address range is changed, the lock is transferred to the private page.

	      The arg parameter is currently unused; however, it must be specified as (zero) for future compatibility.

       Lock in memory all pages mapped by the address space
	      with attributes defined by attr.	This operation is currently not supported.

       Write all modified pages with the attributes defined by
	      attr to their backing storage, and if specified, invalidate the cache copies.

	      For  modified  pages that are mapped as shared the backing storage is the file to which the page is mapped.  For modified pages that
	      are mapped as private the backing storage is its swap area.

	      The arg parameter is a bit pattern built from the following flags:

       Performs asynchronous write operations
	      and returns once all write operations are scheduled.

       Performs synchronous write operations
	      and returns after all write operations are complete.

       Invalidates the mappings of cache copies in memory,
	      forcing all future references of the pages to be obtained from the backing storage location by the system.  Use this  operation  for
	      applications that require a memory object to be in a known state.

       Unlocks all pages in the range that have the attributes specified by
	      attr.

	      The arg parameter is unused, but it must be

       Removes address space memory locks
	      and  locks  on all pages in the address space that have the attributes specified by the attr parameter.  This operation is currently
	      not supported.

   Notes
       The address range specified by addr must be created by a successful call to The page mapping selection attributes  and  are  currently  not
       supported.

RETURN VALUES
       The function returns

	      Success.
	      Failure.
		     is set to indicate the error.

ERRORS
       If fails, may be set to one of the following values.

       There is not enough lockable memory in the system to satisfy
		      the locking request.

       The	      addr parameter does not specify a multiple of the page size as returned by the routine.

       The	      len parameter was specified as zero.

       The address range specified by
		      addr and len was not created by a successful call to

       Indicates that part or all of the addresses in the range
		      (addr, addr+len) are invalid as the address space of the process or pages not mapped are specified.

       An invalid or unsupported
		      cmd parameter was specified.

       The effective user ID of the process is not superuser and
		      or was specified.

AUTHOR
       was developed by HP.

SEE ALSO
       mlock(2), mlockall(2), mmap(2), mprotect(2), msync(2), plock(2), sysconf(2).

																	memcntl(2)