munlock - reenable paging for some parts of memory
int munlock(const void *addr, size_t len);
munlock reenables paging for the memory in the range
starting at addr with length len bytes. All pages which
contain a part of the specified memory range can after
calling munlock be moved to external swap space again by
Memory locks do not stack, i.e., pages which have been
locked several times by calls to mlock or mlockall will be
unlocked by a single call to munlock for the corresponding
range or by munlockall. Pages which are mapped to several
locations or by several processes stay locked into RAM as
long as they are locked at least at one location or by at
least one process.
On POSIX systems on which mlock and munlock are available,
_POSIX_MEMLOCK_RANGE is defined in <unistd.h> and the
value PAGESIZE from <limits.h> indicates the number of
bytes per page.
On success, munlock returns zero. On error, -1 is
returned, errno is set appropriately, and no changes are
made to any locks in the address space of the process.
ENOMEM Some of the specified address range does not corre
spond to mapped pages in the address space of the
EINVAL len was not a positive number.
mlock(2), mlockall(2), munlockall(2)