Despite the name, cppreference is the best online (there's always `man 3`, of course) resource I've found for C, too. MSDN is good for C++ as well (usually the

Despite the name, cppreference is the best online (there's always `man 3`, of course) resource I've found for C, too. MSDN is good for C++ as well (usually the second place I check). And the GCC and Clang documentation is generally pretty comprehensive about compiler-specific stuff. The C and C++ sections of StackOverflow are good for finding language lawyers who can give you an exact answer, with citations, to "is this snippet well-defined?" type questions (the TL;DR is usually "if you have to ask, then it isn't"). But they'll scold you for tagging those sorts of questions with both C and C++, even though it's perfectly reasonable to do.• — • If you're asking about C, it's helpful to know whether your program will still have the same behavior when compiled as C++; if you're asking about C++ but your snippet doesn't have anything C++-specific, it's helpful to future viewers if the answers for both languages are in the same place, since more often than not they're the same (which also means it's helpful to make it clear when they aren't).