What does the C++ standard state the size of int, long type to be?

Question

I\'m looking for detailed information regarding the size of basic C++ types. I know that it depends on the architecture (16 bits, 32 bits, 64 bits) and the compiler.

Answer 1

In practice there's no such thing. Often you can expect std::size_t to represent the unsigned native integer size on current architecture. i.e. 16-bit, 32-bit or 64-bit but it isn't always the case as pointed out in the comments to this answer.

As far as all the other built-in types go, it really depends on the compiler. Here's two excerpts taken from the current working draft of the latest C++ standard:

There are five standard signed integer types : signed char, short int, int, long int, and long long int. In this list, each type provides at least as much storage as those preceding it in the list.

For each of the standard signed integer types, there exists a corresponding (but different) standard unsigned integer type: unsigned char, unsigned short int, unsigned int, unsigned long int, and unsigned long long int, each of which occupies the same amount of storage and has the same alignment requirements.

If you want to you can statically (compile-time) assert the sizeof these fundamental types. It will alert people to think about porting your code if the sizeof assumptions change.