When I clean, build and run my XCode project all goes well, but if I open a file that calls the function, an Use of undeclared identifier 'func()' appears. This is the whole implementation:
The function is called:
func();
And 'func()' is decleared in a .h file like so:
#if __cplusplus
extern "C" {
#endif
extern void func();
#if __cplusplus
}
#endif
and func() is implemented is a cplusplus library.
Why would the error ONLY appears if the file is open, but if I don't open it, it runs and works just fine?