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error: 'INT32_MAX' was not declared in this scope

Answer 1

+3 A:

Quoted from the man page, "C++ implementations should define these macros only when __STDC_LIMIT_MACROS is defined before is included".

So try:

#define __STDC_LIMIT_MACROS
#include <stdint.h>

Blindy 2010-07-12 23:30:51

Thanks! I missed that when reading the man page -_-, I need to wait 7 min before accepting your answer though...

jm1234567890 2010-07-12 23:35:14

Answer 2

+3 A:

 #include <stdint.h> //or <cstdint>
 #include <limits>

 std::numeric_limits<int32_t>::max();

but please note that <cstdint> nor <stdint.h> (which is C header) isn't a part of C++ standard library.

doc 2010-07-12 23:41:35

Note that this isn't equivalent as it can't be used as a compile-time constant (pre-C++0x that is).

Georg Fritzsche 2010-07-12 23:43:21

yes! This is what I am looking for, a C++ way to do it. Thanks

jm1234567890 2010-07-12 23:44:06

@Georg Fritzsche: it can be used as compile-time constant. `const int MY_INT32_MAX = std::numeric_limits<int32_t>::max();` will work just fine. This method is so simple that it will be optimized out as it would be explicitly defined constant.

doc 2010-07-12 23:48:57

If you use `<cstdint>` and compile with `-std=c++0x`, `INT32_MAX` is defined as a constant anyway (At least over here it is [GCC 4.4.4]).

tjm 2010-07-12 23:53:44

Doc, its not a *compile-time* constant - you can't use that where the language requires an *integral constant*. Try `switch(1) { case std::numeric_limits<int32_t>::max(): }` or `struct X { static const int i = std::numeric_limits<int32_t>::max(); };`. I'm btw not saying `<limits>` is bad, just pointing out a difference.

Georg Fritzsche 2010-07-13 01:50:45

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