Try using #ifdef. For example:
#ifdef __CYGWIN__
// Cygwin specific code
#else
// Other code
#endif
Question
I was trying to detect target operating system using c macros _WIN32 and _ CYGWIN_ but it shows error that _ CYGWIN_ is undeclared. How to use these macros to find target operating system
Solution
Try using #ifdef. For example:
#ifdef __CYGWIN__
// Cygwin specific code
#else
// Other code
#endif
OTHER TIPS
gcc on cygwin defines the macro __CYGWIN32__
.
Take a look at GCC dump preprocessor defines to find all the macros defined by the preprocessor.