atomic_cmpxchg(3) atomic_cmpxchg functions.

int atomic_cmpxchg(volatile global(3clc) int *p, int cmp, int val);
unsigned int atomic_cmpxchg(volatile global(3clc) unsigned int *p, unsigned int cmp, unsigned int val);
int atomic_cmpxchg(volatile local(3clc) int *p, int cmp, int val);
unsigned int atomic_cmpxchg(volatile local(3clc) unsigned int *p, unsigned int cmp, unsigned int val);


Read the 32-bit value (referred to as old) stored at location pointed by p. Compute (old == cmp) ? val : old and store result at location pointed by p. The function returns old.

A 64-bit version of this function, atom_cmpxchg(3clc), is enabled by cl_khr_int64_base_atomics(3clc).


m[blue]OpenCL Specificationm[][1]


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OpenCL Specification
page 279, section 6.12.11 - Atomic Functions for 32-bit integers