Read-only

These defines can be checked within the source code to query various system aspects. Example:

#ifdef __AROS__
#warning "Yeah, we build for AROS"
#else
#warning "Sky is falling"
#endif

__AROS__

Check whether we build for AROS.

__i386__, __x86_64__, __mc68000__, __powerpc__, __arm__

On which CPU we are running.

AROS_BIG_ENDIAN

Is 0 on little endian and 1 on big endian systems.

There are many more which you can find in the "Developer/include/aros" directory.

Read/Write

Example usage in a mmakefile.src::

USER_CPPFLAGS := -DPOSIXC_NO_VAARGS

POSIXC_NO_VAARGS

Makes it use #define fwrite __posixc_fwrite instead of #define fwrite(...) __posixc_fwrite(__VA_ARG__).

POSIXC_NOINLINE_VAARGS

It's needed for c++ code. It prevents the defines and the inlines being used, and instead uses the c++ wrappers.

NO_POSIX_WRAPPERS

Prevents posixc using the wrappers at all and passes through to stdcio for symbol definitions.