Are there any macros to determine if my code is being compiled to Windows? [duplicate]

Answer 1

% touch foo.C ; g++ -dM -E foo.C

Will do a nice job of listing all the macros (#define's) automagically defined for you by your [machine specific] g++ compiler.

There might be something similar for Microsoft's compilers...

Answer 2

[Edit: I assume you want to use compile-time macros to determine which environment you're on. Maybe you want to determine if you're running on Wine under Linux or something instead of Windows, but in general, your compiler targets a specific environment, and that is either Windows (DOS) or it isn't, but it's rarely (never?) both.]

Some compilers offer macros to indicate a Windows build environment. But these will vary from compiler to compiler, and even on the same compiler on Windows if the target environment is not exclusively windows. Usually it's __WIN32__, but not always.

#if defined (__WIN32__)
  // Windows stuff
#endif

Sometimes it can be _WIN32, __CYGWIN32__, or possibly just the compiler indicator (_MSC_VER).

If you know the environment you'll be building in (from the makefile) then you can usually pass in the #define on the command line, like "g++ -D __WIN32__ yourfile.c".

A little more info here

Answer 3

These three lines will help you with detection, first we or most of the predefined windows hints together into one OS_WIN macro definition:

#if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)
#define OS_WIN
#endif

Then you can check for it using the preprocessor ifdef:

#ifdef OS_WIN
//Windows specific stuff
#else
//Normal stuff
#endif

Answer 4

Actually I would go with the Environment. getenv() is a standard library function and so is probably the only potentially portable way to do this. The trick is figuring out what variables are unique to all OSes. Windows has ComSpec, appdata, Windir, systemroot and systemdrive which should be set. You could also strstr the path variable for WINDOWS or WINNT but that might not be accurate. I'm not Linux shell/Solaris/MacOS expert so someone else might be able to tell you what "standard" environment variables exist in those OSes. CygWin may cause you some issues, too.

Answer 5

This thing works in visual studio 2012, and other cgwin's g++ compiler. Cut and paste it around but this is generally as thin as it gets All it does is detect windows op systems. Just apply quantification: If not win Then *inux :D enjoy

#include <string>
#include <iostream>
#include <fstream>
#include <cstdlib>
Using namespace std;


int main(){    
    char chCap;    int i = 0;
    const int MAX_BUFFER = 70; 
    char buffer[MAX_BUFFER];

    string cmd="ver";   
    FILE *stream = _popen(cmd.c_str(), "r");

    if (0 != stream){
        while (!feof(stream)){  
            //One way is here
            //chCap = fgetc(stream);
            //cout << chCap;
            //buffer[i++] = chCap;

            //This one seams better
            fgets(buffer, MAX_BUFFER, stream);      
        }
        _pclose(stream);
    }       
    cout << endl;
    cout << buffer << endl;

    //The op sys detection starts here
    string opSys(buffer);   //char array to string
    if("Microsoft" == opSys.substr(0,9)){
        cout << "You are in a Microsoft envornment " << endl;
    }
    system("pause");
    return 0;    
}