Compiler directives (#ifdef's) to isolate specific compilers

Below are a list of different compiler defines that are handy to know when you need to write cross-compiler compatible code and need to isolate certain features to certain compilers.

GNU gcc

#ifdef __GNUC__
  // GNU C
#ifdef __GNUC_MINOR__
 // GNU C MINOR
#if __GNUC_PATCHLEVEL__
 // GNU C PATCH LEVEL
#endif
#endif
#endif
 
#if (__CYGWIN32__ || __CYGWIN__)
  // CYGWIN
#endif
 
#if (__MINGW32__ || __MINGW__ ) 
  // MINGW
#endif
 
#if (__DJGPP__)
  // DJGPP
#ifdef __DJGPP_MINOR__
  // DJGPP MINOR
#endif
#endif
 
#endif

Microsoft C++

#ifdef _MSC_VER
  // Microsoft C++
 
#ifdef _MANAGED
#if (_MANAGED)
  // Managed
#else
  // Unmanaged
#endif
#else
  // Unmanaged
#endif
#endif

Borland C++

#ifdef __BCPLUSPLUS__
  // Borland C++ 
#endif

Digital Mars C++

#ifdef __DMC__
#ifndef __DMC_VERSION_STRING__
#error __DMC_VERSION_STRING__ Not Defined
#endif
  // Digital Mars C++
#endif

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