I just can't get my head around why this won't compile. I have three files: main.cpp #include "expression.h" int main(int argc, char** argv) { return 0; } expression.h #ifndef _EXPRE...

I am trying to exclude some parts of a Swift file for a specific target. Yet I did not find any replacement of the #ifndef objective-c directive and moreover if I use a form of the kind: #if taxi_...

All across our C code base, I see every macro defined the following way: #ifndef BEEPTRIM_PITCH_RATE_DEGPS #define BEEPTRIM_PITCH_RATE_DEGPS 0.2f #endif #ifndef BEEPTRIM_ROLL_RATE_DEGPS #define ...