How can I modify my own C header files so its easier to #include them in C++ code?
If you are including a C header file that isn’t provided by the system, and if you are able to change the C header, you should strongly consider adding the extern C {…} logic inside the header to make it easier for C++ users to #include it into their C++ code. Since a C compiler won’t understand the extern C construct, you must wrap the extern C { and } lines in an #ifdef so they won’t be seen by normal C compilers. Step #1: Put the following lines at the very top of your C header file (note: the symbol __cplusplus is #defined if/only-if the compiler is a C++ compiler): #ifdef __cplusplus extern “C” { #endif Step #2: Put the following lines at the very bottom of your C header file: #ifdef __cplusplus } #endif Now you can #include your C header without any extern C nonsense in your C++ code: // This is C++ code // Get declaration for f(int i, char c, float x) #include “my-C-code.h” // Note: nothing unusual in #include line main() { f(7, ‘x’, 3.14); // Note: nothing unusual in the call
