NAME
	  plock	-  Locks a process' text and/or	data segments in
	  memory

     SYNOPSIS
	  #include <sys/lock.h>
	  int plock(
	       int opr)	;


     PARAMETERS
	  opr	    Specifies one of the following operations:


		    PROCLOCK  Locks the	text and data segments into
			      memory.

		    TXTLOCK   Locks the	text segment into memory.

		    DATLOCK   Locks the	data segment into memory.

		    UNLOCK    Removes locks.


     DESCRIPTION
	  The plock() function locks or	unlocks	a process' text	seg-
	  ments, data segments,	or both	in physical memory.  When
	  locked, the physical pages containing	the text or data seg-
	  ment will not	be paged out.  It is an	error to lock a	seg-
	  ment that is already locked.

	  The caller must have superuser privilege to use the plock()
	  function.

	  Note that memory acquired subsequent to a plock() function
	  may or may not be locked in memory, depending	on the
	  specific acquisition method.	Memory acquired	using the
	  brk()	function (or the sbrk()	function) will be locked if
	  the data segment was locked.	Memory acquired	via the	mmap()
	  or vm_allocate() functions will not be locked.

     RETURN VALUES
	  Upon successful completion, a	value of 0 (zero) is returned
	  to the calling process.  Otherwise, a	value of -1 is
	  returned and	errno is set to	indicate the error.

     ERRORS
	  If the plock() function fails, errno may be set to one of
	  the following	values:


	  [EPERM]   The	caller does not	have appropriate privilege.
	  [EAGAIN]  There are insufficient resources to	perform	the
		    operation.

	  [EINVAL]  The	opr parameter is PROCLOCK, but the text	seg-
		    ment or the	data segment is	already	locked.

	  [EINVAL]  The	opr parameter is TXTLOCK, but the text segment
		    is already locked.

	  [EINVAL]  The	opr parameter is DATLOCK, but the data segment
		    is already locked.

	  [EINVAL]  The	opr parameter is UNLOCK, but neither the text
		    segment nor	the data segment is locked.


     RELATED INFORMATION
	  Functions: brk(2), mmap(2)