3 ms·
It's absolutely insanity. A cruel question I came up with the other day, based on it - What is the result of: std::is_signed<decltype(1L * 2U)>() ?
by MaulingMonkey 6y ago
It's absolutely insanity. A cruel question I came up with the other day, based on it - What is the result of:
std::is_signed<decltype(1L * 2U)>()
?
- folmar 6y agoWhy should it be cruel? Promotions are a part of life of an integer in C.
- MaulingMonkey 6y agoEven programmers who are roughly aware of integral promotion rules may not have connected all the dots to realize the answer is implementation dependent. If sizeof(long) == sizeof(unsigned int), 1L * 2U results in an unsigned int, meaning the result is "false". If sizeof(long) > sizeof(unsigned int), 1L * 2U result in a signed long, meaning the result is "true".
- mehrdadn 6y agoWow that is cruel! Somehow I just assumed int would get promoted to long regardless of their size difference. That this isn't the case almost seems like a language defect!