size of int variable

Question

How the size of int is decided?

Is it true that the size of int will depend on the processor. For 32-bit machine, it will be 32 bits and for 16-bit it's 16.

On my machine it's showing as 32 bits, although the machine has 64-bit processor and 64-bit Ubuntu installed.

Answer 1

It depends on the implementation. The only thing the C standard guarantees is that

sizeof(char) == 1

and

sizeof(char) <= sizeof(short) <= sizeof(int) <= sizeof(long) <= sizeof(long long)

and also some representable minimum values for the types, which imply that char is at least 8 bits long, int is at least 16 bit, etc.

So it must be decided by the implementation (compiler, OS, ...) and be documented.