Compares atomic to oldval and, if equal, sets it to newval.
If atomic was not equal to oldval then no change occurs.
This compare and exchange is done atomically.
Think of this operation as an atomic version of `{ if (*atomic == oldval) { *atomic = newval; return TRUE; } else return FALSE; }`.
This call acts as a full compiler and hardware memory barrier.
| atomic |
a pointer to a |
| oldval |
the value to compare with |
| newval |
the value to conditionally replace with |
|
true if the exchange took place |