| Space | User/kernel |
| Context | Sync/async/rt-irq |
| May block | No |
| SPL | Any |
| Dynamic memory | No |
Preprocessor macro expanding to an expression
#include <ARCH/BITOPS.H>
if (__CMPXCHG64_AVAILABLE) ... This macro returns non-zero if inline functions __CMPXCHG64 and __LOCK_CMPXCHG64 are available on a current CPU. If they are not available, they must not be called because that would cause an invalid instruction exception.
Zero, if 64-bit CMPXCHG is not available, otherwise non-zero.