Portable typedefs for ANSI C

Question

I have a portable definition of types in a header of a project that i aim to compile on multiple platforms. I'm using the following typedefs:

#ifndef PLATFORM_H
#define PLATFORM_H

#include <stdio.h>
#include <stdlib.h>
#include <memory.h>

#ifndef TRUE
#define TRUE (1)
#endif

#ifndef FALSE
#define FALSE (0)
#endif

typedef signed char int8_t;
typedef unsigned char uint8_t;
typedef signed int int16_t;
typedef unsigned int uint16_t;
typedef signed long int int32_t;
typedef unsigned long int uint32_t;
typedef signed long long int int64_t;
typedef unsigned long long int uint64_t;

#endif

This header is platform-specific, so i have a similar declaration for every platform, making sure that integers are always the same. However, in compiling, i get this:

conflicting types for ‘int32_t’
In file included from /usr/include/stdlib.h:314:0,
                 from platform.h:5,
                 from main.c:1:
/usr/include/x86_64-linux-gnu/sys/types.h:196:1: note: previous declaration of ‘int32_t’ was here

And other errors. What might be the cause? Can i override a typedef, or check for it's existence first?

Answer 1

You get an error because you picked names for your typedefs that collide with names of types from the <stdint.h> header.

Since you are looking for types that are already defined in stdint.h, you might as well include it on platforms that provide this header.