While checking if correct header file was in use I added #ifdef #pragma ... #endif preprocessor directives. The pragma message I was expecting in compiler output was not there.
So I just added #pragma message without the #ifdef ...#endif block and got multiple messages in compiler output.
Does that meas the entire header file was somehow (partially) included in source code multiple times?
Does that indicates that the standard #ifndef #define ...#endif preprocessor directives included in EVERY header file is also ignored?
And this " multiple include guards" stops the compiler to see multiple definitions?
Here is partial compiler output
/home/jim/.arduino15/packages/arduino/hardware/sam/1.6.8/cores/arduino/Print.h Multiple include guards may be useful for:
Just asking. Jim