Size of integer in C [duplicate]

Question

Possible Duplicate:
Does the size of an int depend on the compiler and/or processor?

Does the size of Integer depend on Compiler or on OS or on Processor? What if I use gcc on both 32 bit OS or 64bit OS running either on 32 bit machine or 64 bit machine(only 64 bit OS in this case).

Answer 1

It depends on the combination of compiler, processor and OS.

For instance, on a 64 bit Intel CPU, in 64 bit mode, the size of a long int in Windows is 4 byte while in Linux and on the Mac it is 8 byte. int is 4 bytes in all three OSes on Intel.

The compiler implementer also has a choice, but usually uses what the OS uses. But it could well be that a compiler vendor that has C compilers for all three platforms decides to use the same sizes in all three.

Of course, it doesn't make sense to make int 4 bytes (although it would be possible) on a 16 bit CPU.

So it depends on all three things you mention.