including header file based on OS.

[rajatgirotra]

Hi Everyone

I have 2 header files; say linuxstdio.h and windowsstdio.h in my project source.

/project/src/linux/include/linuxstdio.h
/project/src/windows/include/windowsstdio.h

I want to include one of these in my build depending on the target i am building it for (linux or windows).

i want to do this in the following way..

#include <project/src/__OS__/include/__OS__stdio.h 

Is there a way i can set the __OS__ variable in my build environment and have my C++ compiler pick it up from there?

This is just a simple example of what i want to do. To be specific; i have N such headers files; so i must follow this simple approach; unless there is smthing more simpler..

[writetonsharma]

#ifdef WIN32
/project/src/windows/include/windowsstdio.h
#endif

#ifdef __linux__
/project/src/linux/include/linuxstdio.h
#endif 

[rajatgirotra]

Oh i just realised i asked the wrong query.. apologies..

actually i want to include BOTH the headers.. and i want to do it this way..

#include <project/src/__OS__/include/__OS__stdio.h> 

Is there a way i can set the __OS__ variable in my build environment and have my C++ compiler pick it up from there?

This is just a simple example of what i want to do. To be specific; i have N such header files; so i must follow this simple approach; unless there is smthing more simpler..

[writetonsharma]

you can define a variable and then you can compile.
i give you an example of gcc

do this:
export __OS__=<your value>

compile the code with a -D __OS__
like:
g++ -D __OS__ file_name

NOTE: its -D if i remember it correctly.

you code will take the value of __OS__ now, what ever it will be

if you do this:
export __OS__=MyVal1

#ifdef MyVal1

//this will compile if __OS__ value is MyVal1
#endif

#ifdef MyVal2

//this will only compile if __OS__ value is Myval2
#endif


i dont know about ms vc, how to do that in that.
hope this is what you want.