Subject: Re: `-ffreestanding'
To: matthew green <email@example.com>
From: Richard Earnshaw <firstname.lastname@example.org>
Date: 07/16/2001 11:15:56
> > i'm going to add this flag to LKM building, as well as the kernels for
> > ports i can test. it disables internal `printf' prototype mismatch,
> > as well as `main' warnings that -Wno-main does not get rid of.
> Sadly this will also disable all builtin functions (in particular things
> like builtin memcpy) unless we take steps to prevent this by adding
> -fbuiltin *after* -ffreestanding.
> unfortunately, we *don't* want the builtin `printf' because it's wrong.
> these builtins should really have their own -fswitches each. :-(
Printf isn't a builtin (at least, not in that sense). So adding -fbuiltin
will not re-enable the format warning checker.
Another alternative is to have a header file (say k-builtin.h) which
#defines the things we want builtin to their __builtin_foo equivalents.
This would then provide the functionality we require.
#define memcpy(x,y,z) __builtin_memcpy(x,y,z)