freebsd man page for vslock

VSLOCK(9)						   BSD Kernel Developer's Manual						 VSLOCK(9)

NAME
     vslock, vsunlock -- lock/unlock user space addresses in memory

SYNOPSIS
     #include <sys/param.h>
     #include <sys/proc.h>
     #include <vm/vm.h>
     #include <vm/vm_extern.h>

     int
     vslock(void *addr, size_t len);

     void
     vsunlock(void *addr, size_t len);

DESCRIPTION
     The vslock() and vsunlock() functions respectively lock and unlock a range of addresses belonging to the currently running process into mem-
     ory.  The actual amount of memory locked is a multiple of the machine's page size.  The starting page number is computed by truncating addr
     to the nearest preceding page boundary, and by rounding up addr + len to the next page boundary.  The process context to use for this opera-
     tion is taken from the global variable curproc.

RETURN VALUES
     The vslock() function will return 0 on success, otherwise it will return one of the errors listed below.

ERRORS
     The vslock() function will fail if:

     [EINVAL]		The addr and len parameters specify a memory range that wraps around the end of the machine address space.

     [ENOMEM]		The size of the specified address range exceeds the system limit on locked memory.

     [EFAULT]		Some portion of the indicated address range is not allocated.  There was an error faulting/mapping a page.

BSD
								  August 29, 2012							       BSD