Want the word on __STDC__

[Lars Wirzenius]

In article <lampblack at dce.ie>, em at dce.ie (Eamonn McManus) writes:
> If I want my code to run on pre-standard implementations (which presumably
> I do if I care about __STDC__) then I am reluctant to depend on
>   #if __STDC__
> or
>   #if __STDC__ == 1
> rather than
>   #ifdef __STDC__
> which would have been safe had it not been for cretinous implementors who
> made half-standard implementations with __STDC__ defined but 0.

How about:

#ifndef STD_C
#    ifdef __STDC__
#        if __STDC__ == 1
#            define STD_C
#        endif
#    endif
#endif

and then code the rest of the program depending on STD_C instead of
__STDC__? 

Incidentally, I would think that it would be better (or at least more
useful) to use constants that describe characteristics of the system,
rather than conformance to the standard.  For example, I think
prototypes are available in several non-standard (or almost standard)
implementations, which don't do the Right Thing for __STDC__.  Another
example is header files.  The standard introduces <limits.h> (doesn't
it?), which may or may not be available in non-standard implementations. 
It might be a local enchancement to make standard conforming programs to
compile a teeny bit easier, but might not be available on other sites
with the same C implementation. 

-- 
Lars Wirzenius    wirzenius at cc.helsinki.fi