CPP defines...

[Nick Crossley]

In article <179 at istop.ist.CO.UK> rb at ist.CO.UK (News reading a/c for rb) writes:
>Here's a nasty little script that comes in useful when you
>want to know what your cpp *really* predefines: we have found
>that the man page is sometimes economical with the truth.
> ...
>strings -a -2 /lib/cpp | sed '/^a-zA-Z0-9_/!s/.*/#ifdef &\
>"%&"\
>#endif/p' |/lib/cpp |sed -n '/%/s/[%"]//gp'

Ah, but not all systems have their predefined symbols defined by cpp!  I know
of some which define some symbols in cc!  Thus, a better? more complete?
approach might be :-

strings <options as required> /lib/cpp /bin/cc |
sort -u |
sed -n '/^[a-zA-Z0-9_]*$/s//#ifdef &\
"%&"\
#endif/p' >cpp_test.c

cc -E cpp_test.c |
sed -n '/%/s/[%"]//gp'
-- 

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Nick Crossley, CCI, 9801 Muirlands, Irvine, CA 92718-2521, USA
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