Identify the platform linux or windows using C/C++ code

Question

I was asked in an interview to how would you identify the platform only by providing runnable C code? The code must be runnable in both platform(i.e no special header files function used to check)?

Accepted Answer

a quick google search shows this

```
#if defined(_WIN64)
    /* Microsoft Windows (64-bit). ------------------------------ */

#elif defined(_WIN32)
    /* Microsoft Windows (32-bit). ------------------------------ */

#endif
```

OS identification macros are predefined by all C/C++ compilers to enable #if/#endif sets to wrap OS-specific code. This is often necessary in cross-platform code that must use low-level library functions for fast disk I/O, inter-process communications, or threads. While differences between Windows and other OSes are acute, even differences among UNIX-style OSes can require #if/#endif constructs. This article surveys common compilers and shows how to use predefined macros to detect common OSes at compile time.

http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system

Identify the platform linux or windows using C/C++ code

Solution

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