Determining whether compiling on Windows or other system

Question

I'm currently developing a cross-platform C application. Is there any compiler macro which is defined only during compilation on Windows, so I can #ifdef some Windows specific #includes?

Typical example is selecting between WinSock and Berkeley sockets headers:

#ifdef _WINDOWS
   #include <winsock.h>    
#else
   #include <sys/socket.h>
   #include <netinet/in.h>
   #include <sys/un.h>
   #include <arpa/inet.h>
   #include <netdb.h>
#endif

So the thing I'm looking for is something like that _WINDOWS macro.

James McNellis · Accepted Answer · 2010-04-05T15:30:10.133

11

Your best bet is to use

_WIN32

It is guaranteed to be defined when compiling for a 32-bit or 64-bit Windows platform using the Visual C++ compiler. I would expect other compilers for Windows to define it as well (the Intel C++ compiler defines it, as does the MinGW gcc).

edited Apr 05 '10 at 15:30

answered Apr 05 '10 at 15:19

James McNellis

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And what in case of 64-bit Windows? I presume _WIN32 is defined only on 32 bit systems, right? – NumberFour Apr 05 '10 at 15:21
3

The 32 is really there to separate it from ancient 16-bit versions of Windows. Removing that definition in Win64 would've broken too much stuff, so it was less hassle to leave it in. – Matti Virkkunen Apr 05 '10 at 15:28

score 3 · Answer 2 · answered Apr 05 '10 at 15:24

3

Use _WIN32.

Reference:

Microsoft C++ Predefined Macros
GCC Predefined Macros
How to get predefined macros for OS X (or just check for __APPLE__)

answered Apr 05 '10 at 15:24

Josh Kelley

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score 2 · Answer 3 · answered Apr 05 '10 at 15:23

2

_WIN32

Defined for applications for Win32 and Win64. Always defined.

_WIN64

Defined for applications for Win64.

Source : Lists the predefined ANSI C and Microsoft C++ implementation macros.

answered Apr 05 '10 at 15:23

anno

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Determining whether compiling on Windows or other system

3 Answers3