Side with effete.

More of „I know C better than you!“ stuff.

I just discovered (the verb is deeply characteristic) how to write a HAS_SIDE_EFFECTS(expr) macro that doesn't evaluate expr and returns true iff expr has side-effects.

The macro essentially depends on a GCC extension. It is useful, for example, as a sanity check in conditionally compiled code, e.g., in assert(expr).