Size of Int on a machine

[aruna]

How do I check the size of int on a machine before
runtime, at the pre-processor stage? Is it possible?

 

[Eric Sosman]

How do I check the size of int on a machine before
runtime, at the pre-processor stage? Is it possible?

Not in Standard C, although some implementations allow
it as a non-conforming extension. What you *can* do, though,
is check the range of an int, using the INT_MAX and INT_MIN
macros defined in <limits.h>. For example,

#include <limits.h>
#if INT_MAX >= 1000000
typedef int Million;
#else
typedef long Million;
#endif

 

[Kip Neuhart]

How do I check the size of int on a machine before
runtime, at the pre-processor stage? Is it possible?

You can't do it directly in standard C. Perhaps this is a sign that your
code relies on machine specifics too much?

 

[CBFalconer]

How do I check the size of int on a machine before
runtime, at the pre-processor stage? Is it possible?

#include <limits.h>

#if (INT_MAX < nnnL)
# error "int too small"
#endif

It might be simpler to use longs for the appropriate variables.

 

[Dan Pop]

How do I check the size of int on a machine before
runtime, at the pre-processor stage? Is it possible?

Yup. Include <limits.h> and examine INT_MAX.

Dan

 

[Vijay Kumar R Zanvar]

How do I check the size of int on a machine before
runtime, at the pre-processor stage? Is it possible?

A simple method would to consult the documentation,
if any, that came with the compiler.