A global function may be declared inline. If you use the same function in different development environments, e.g., C and C++, you can hide the “inline” keyword from a C compiler while keeping it visible to a C++ compiler like this:

 #ifndef __cplusplus#define inline#endif

The preprocessor directives make sure that only a C++ compiler sees the inline keyword:

 inline int get_dst() {return dst; }// inline not seen by C