Thread: Concepts of memory

Originally Posted by Elkvis

what the standard guarantees is this: sizeof(char) <= sizeof(short) <= sizeof(int) <= sizeof(long) <= sizeof(long long)

Not true. In practice it usually works out that sizeof(char) <= sizeof(short) <= sizeof(int) <= sizeof(long) <= sizeof(long long). However, that is not actually a requirement in the standard.

The standard only requires that the set of values that can be represented by a char is a subset of the values that can be represented by a short, which in turn is a subset of the values that can be represented by a short .....

Originally Posted by CornedBee

The fun thing? The standard never defines what "providing storage" means. So it's actually somewhat open to interpretation. I would personally actually go more with the sizeof interpretation than the value range interpretation.
I don't have the C standard to check what that says, though.

The C standard only talks about the ranges of values that can be represented. It does not make reference to sizeof() at all in discussing storage of a value in an integral (or any other) type.

Part of the ambiguity is that the word "storage" can mean "representing a value using a variable" as well as "allocating memory".

Originally Posted by grumpy

Not true. In practice it usually works out that sizeof(char) <= sizeof(short) <= sizeof(int) <= sizeof(long) <= sizeof(long long). However, that is not actually a requirement in the standard.

The standard only requires that the set of values that can be represented by a char is a subset of the values that can be represented by a short, which in turn is a subset of the values that can be represented by a short .....

Regardless of how numbers are represented, fundamental mathematics seems to imply that if the above statement is true, then the statement about sizeof() is also true. You can't have sizeof(short) < sizeof(char) if short can represent every value that char can represent.