Windows and Linux with c cross platform. How to hide a function?

Question

I have written a code which should work both in Linux and Windows. For windows I have written a specific program that uses functions and capabilities only available in windows i.e. it does not work in Linux.

My program header:

#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#if defined (_WIN32)
# include <direct.h>
# include <windows.h>
# define getcwd _getcwd
# define PATH_SEPARATOR "\\"
# define snprintf _snprintf
# define flag 2 //flag is 2 in windows
# define strdup   _strdup
# define fileno   _fileno
#else
# include <unistd.h>
# include <dirent.h>
# define PATH_SEPARATOR "/"
# define flag 1//on linux the flag is 1
# define sprintf_s snprintf
# define getch() getchar()
# define malloc (char*)malloc
#endif

Now I have a function that only works with windows and gives loads of errors when I try to compile on Linux.

void funtionForWindowsOnly(){

   //some things that I can only do on windows for Linux I will write a new program
}

So in my main I have done this

main(){

if(flag==2)//i.e. in case of windows do this
{
       funtionForWindowsOnly();
}

}

But when I try to do this Linux gives me loads of errors as it is trying to compile the function

void funtionForWindowsOnly();

My question is how can I leave this function funtionForWindowsOnly() in my program and my program still successfully compiles using Linux?

I think there is a way of doing #ifdef or something like this using preprocessors. Or maybe there is another simple way. Please help. If you require any further information please let me know.

As soon as I posted it the answer came to me... but thanks @MartinJames. — ITguy, Nov 16 '15 at 11:06

score 2 · Accepted Answer · answered Nov 16 '15 at 11:04

You can place #ifdef #else inside the function you want both in windows & linux. like something following

void unifiedFunction()
{
    #ifdef _WIN32
        //windows specific implementation goes here
    #elif
        //other platform like linux
    #endif

}

In my repository i have a same issue when bringing platform independency. You can check my implementation here

Windows and Linux with c cross platform. How to hide a function?

1 Answers1