###### (This is the legacy documentation for stable SDL2, the current stable version; [SDL3](https://wiki.libsdl.org/SDL3/) is the current development version.)
# SDL_MemoryBarrierReleaseFunction

Memory barriers are designed to prevent reads and writes from being reordered by the compiler and being seen out of order on multi-core CPUs.

## Header File

Defined in [SDL_atomic.h](https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_atomic.h), but apps should _only_ `#include "SDL.h"`!

## Syntax

```c
void SDL_MemoryBarrierReleaseFunction(void);

```

## Remarks

A typical pattern would be for thread A to write some data and a flag, and
for thread B to read the flag and get the data. In this case you would
insert a release barrier between writing the data and the flag,
guaranteeing that the data write completes no later than the flag is
written, and you would insert an acquire barrier between reading the flag
and reading the data, to ensure that all the reads associated with the flag
have completed.

In this pattern you should always see a release barrier paired with an
acquire barrier and you should gate the data reads/writes with a single
flag variable.

For more information on these semantics, take a look at the blog post:
http://preshing.com/20120913/acquire-and-release-semantics

## Version

This function is available since SDL 2.0.6.

----
[CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction)