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

       Copyright © 2012-2014 Khronos Group

[FIXME: source]                                    11/18/2024                                 ATOMICCOMPSWAP(3G)

intatomicCompSwap(inoutintmem,uintcompare,uintdata);uintatomicCompSwap(inoutuintmem,uintcompare,uintdata);

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.

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

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

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

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

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       │                │        OpenGLShadingLanguageVersion                                            │
       ├────────────────┼──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┤
       │ 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 │  -   │  -   │  -   │  -   │  -   │  -   │  -   │  -   │  -   │  ✔   │  ✔   │  ✔   │
       └────────────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘