Preprocessor numbers

[Doug Gwyn]

In article <10892 at riks.csl.sony.co.jp> diamond%ws.sony.junet at uunet.uu.net (Norman Diamond) writes:
>In evaluating the constant-expression of a #if directive, any
>identifiers that are left over after macro substitution are changed
>into the constant 0.  What about preprocessor numbers that are left
>over after numeric conversion?  For example, 1f0x3 does not convert
>into a long or double.  Should it be replaced by the constant 0?

No, when that pp-number pp-token is converted to a non-pp token before
evaluation of the #if's constant-expression according to the rules of
section 3.4, the resulting "token" will be diagnosed as an invalid C
token.