What is the goal of #If0-ed CPP tokens ?

[Martin von Loewis]

>   CPP_ANDAND, /* "&&" */
[...]
>  What is the goal of text, in block #if 0 ... #endif ?

I believe there is a keyword "and" in ISO C and ISO C++, so you can
write

if(foo() and bar()){
	 some_code();
}

For C, it appears that these keywords are related to iso646.h, whereas
for C++, these should be always there. You'd have to carefully study
the standard to find out whether they are supposed to be:
a) keywords
b) predefined preprocessor defines
c) preprocessor defines associated only with iso646.h

It seems that there is some confusion in gcc, so nobody determined the
state of these tokens for good, either enabling or removing the code.

Regards,
Martin