NAME

       atomicCompSwap - perform an atomic compare-exchange operation to a variable

DECLARATION

       int atomicCompSwap(inout int mem, uint compare, uint data);

       uint atomicCompSwap(inout uint mem, uint compare, uint data);

PARAMETERS

       mem
           The variable to use as the target of the operation.

       data
           The data to be compared and potentially exchanged with mem.

DESCRIPTION

       atomicCompSwap performs an atomic comparison of compare with the contents of mem. If the
       content of mem is equal to compare, then the content of data is written into mem,
       otherwise the content of mem is unmodifed. The function returns the original content of
       mem regardless of the outcome of the comparison. The contents of the memory being updated
       by the atomic operation are guaranteed not to be modified by any other assignment or
       atomic memory function in any shader invocation between the time the original value is
       read and the time the new value is written.

       Atomic memory functions are supported only for a limited set of variables. A shader will
       fail to compile if the value passed to the mem argument of an atomic memory function does
       not correspond to a buffer or shared variable. It is acceptable to pass an element of an
       array or a single component of a vector to the mem argument of an atomic memory function,
       as long as the underlying array or vector is a buffer or shared variable.

VERSION SUPPORT

       ┌───────────────┬───────────────────────────────────────────────────────────────────────────────────┐
       │               │        OpenGL Shading Language Version                                            │
       ├───────────────┼──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┤
       │Function       │ 1.10 │ 1.20 │ 1.30 │ 1.40 │ 1.50 │ 3.30 │ 4.00 │ 4.10 │ 4.20 │ 4.30 │ 4.40 │ 4.50 │
       │Name           │      │      │      │      │      │      │      │      │      │      │      │      │
       ├───────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┤
       │atomicCompSwap │  -   │  -   │  -   │  -   │  -   │  -   │  -   │  -   │  -   │  ✔   │  ✔   │  ✔   │
       └───────────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘

SEE ALSO

       atomicAdd(), atomicAnd(), atomicOr(), atomicXor(), atomicMin(), atomicMax(),
       atomicExchange()

COPYRIGHT

       Copyright © 2011-2014 Khronos Group. This material may be distributed subject to the terms
       and conditions set forth in the Open Publication License, v 1.0, 8 June 1999.
       http://opencontent.org/openpub/.

COPYRIGHT

       Copyright © 2012-2014 Khronos Group

[FIXME: source]                             01/03/2018                         ATOMICCOMPSWAP(3G)