MUNLOCK(2) Linux Programmer's Manual MUNLOCK(2)
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 the kernel.
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_MEM-
LOCK_RANGE is defined in <unistd.h> and the value PAGESIZE from <lim-
its.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 correspond to
mapped pages in the address space of the process.
EINVAL len was not a positive number.
mlock(2), mlockall(2), munlockall(2)
Linux 1.3.43 1995-11-26 MUNLOCK(2)