Luna::atom_compare_exchange_i32

i32 atom_compare_exchange_i32(i32 volatile *dst, i32 exchange, i32 comperand)

Atomically compares the value of the variable with the specified comperand, and sets the variable to the specified value if equal.

Parameters

• in dst

  The pointer to the variable that needs to be compared.

• in exchange

  The value to set to the variable if *dst == comperand.

• in comperand

  The value to compare with.

Return value

Returns the value of the variable before this operation took place.

Remark

The following code demostrates the behavior of this function:

 ++
vtype [atom_compare_exchange_i32](group___runtime_atomic_1gaf678d9768b4d454a41fccf2b33eb1f2a.md)(vtype volatile* dst, vtype exchange, vtype comperand)
{
    vtype r = *dst;
    if(*dst == comperand) *dst = exchange;
    return r;
}