> Date: Thu, 19 Sep 1996 10:41:41 -0700
> From: lgs@psbhns.hk.hq.cn (lgs)
>
> where is the definition for __builtin_constant_p and __outb_p in
> linux kernel source code? I find these function ( macro?) used in
> include/asm/io.h, but I can not find any definition for them.
>
> They are "magic" and embedded internally inside of GCC itself.
True for __builtin_constant_p, and last time I checked it was not
documented :-(, at least not found by a search in info gcc.
But __outb_p it is defined as an inline functions through a few macro layers
generated by the following line:
__OUT(b,"b",char)
looking down the macro expansion is left as an exercise to the reader.
cc -E io.h will show it clearly, but the output is not exacly pretty :-)
Greetings,
Gabriel.