How can I find out cc or cpp symbols?

[Doug Gwyn]

In article <1954 at trantor.harris-atd.com> bbadger at x102c.harris-atd.com (Bernie Badger Jr.) writes:
>Is there a way to find out what macros are defined?  It's particularly hard 
>to predict which names will be _predefined_.  ...

This is not an issue for Standard C, since the only predefined macros
allowed are those specified in the Standard and optionally additional
implementation-specific ones that must have names starting with _.
If you do not use _-names in your application code, it will be impervious
to predefined vendor macros in any Standard conforming implementation;
thus why would you care what they were?

The particular set of predefined vendor macros may very well depend on
the options supplied to the compiler when it is invoked.