Compiler-Warnings not displayed when compiling for Arduino

[mnikander]

I've noticed that when compiling for Arduino, Compiler-Warnings are not shown at all. In the Makefile.arduino the -w compiler option is set, which inhibits all warnings. Why? Removing it doesn't seem to result in a flood of warnings as I'd initially feared.

Nonetheless, even when leaving the -w option out, only some of the warnings are seen when compiling for Arduino (compared to the PC). Is this due to the use of different compilers?