30 ms·
The arg is expanded twice but evaluated zero times, since sizeof gives the size of its argument type without executing anything.
by f33d5173 3y ago
The arg is expanded twice but evaluated zero times, since sizeof gives the size of its argument type without executing anything.
- Izkata 3y agocountof(foo()) looks like foo() is only called once, but would actually be called twice. That's what GP is talking about, it's evaluated twice after the expansion when the code is actually running, not during the expansion.
- deleted 3y ago[deleted]
- uecker 3y agoIt is not evaluated for regular arrays. It is evaluated for arrays with variable size, you need to be careful a bit. But this is rarely happens to be a problem. The general rule for sizeof is to apply it only to variable names or directly to typenames.
- tpush 3y agoAgain no, foo isn't called at all since countof() only uses its argument in a sizeof expression.