Detect if Windows operating system in C++ [duplicate]

Question

How can I detect if the operating system is Windows in C++/C?

Answer 1

#ifdef _WIN32
cout << "This is Windows." << endl;
#endif

This will allow you define blocks for windows only. As long as the preprocessor macro is defined.

This is a compile time thing, not a runtime thing.

Answer 2

You can use getenv() from cstdlib like so:

#include <cstdlib>

getenv("windir");

If you get NULL then it's not windows.

This works since %windir% should only be defined on windows systems. This is a cheap and dirty hack of course.

http://www.cplusplus.com/reference/clibrary/cstdlib/getenv/