long =int?

Int is usually assumed to be the word size on a platform. For 16 bit systems an int is 16 bits and for 32 bit systems an int is 32 bits. For 64 bit systems this holds no longer, here int usually is 32 bits too.

http://www.opengroup.org/public/tech/aspen/lp64_wp.htm

It is probably true in all 32bit computers, in a 16 bit computer (286 Intel CPU and less) sizeof(int) = 2, sizeof(long)=4, in a 64bit CPU int is probably 8, long would be 4 (though I am not sure).

This doesnt make sence, but you have to remember that when long was named long, CPU's were 16 bit at the most.

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Original post by Kwizatz It is probably true in all 32bit computers, ...

... except PS2 (depending on the compiler, of course).

It depends on operating system, and cpu, and compiler, it can be different among different computers that why you should never assume the size of any data type.

It's pretty much up to your compiler, and it's decision can vary depending on the target system/cpu.

All your can be sure of is that short is at least as big as char, int is at least as big as short, and long is at least as big as int.

Quote:

Original post by Kwizatz in a 64bit CPU int is probably 8, long would be 4 (though I am not sure).

I've only used one 64bit OS, but it was vice-versa (sizeof(long)=8, sizeof(int)=4).

Here is the one thing you can rely on:

sizeof (int) <= sizeof (long)

It wouldn't suck for you to make specific defines to use for 8, 16, 32, 64 bit types. Then when you run into a platform where they're not what you think, all you have to do is typedef them correctly rather than single-stepping through your code trying to figure out why everything broke all of the sudden.

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Original post by bobstevens Here is the one thing you can rely on: sizeof (int) <= sizeof (long)

Sorry. The ISO standard only states sizeof(long) >= 4.
Ints on some 64bit systems are 8 bytes big, while longs are 4 bytes in size.