Assorted C Questions

[Alan J Rosenthal]

gdtltr at vax1.acs.udel.EDU (Gary D Duzan) writes:
>how necessary are #if directives?  It seems to me that it adds too much
>complexity to the preprocessor.

Indeed it does add a lot of complexity to the preprocessor.  I think that's why
most people no longer separate the preprocessor and the parser so much these
days.

I don't think expression handling in the preprocessor is SO important.  I
currently use a C implementation lacking it, and I don't really miss it much.
What I do miss is that I also can't say "#if THING" where THING is previously
#defined to be zero or non-zero.  Do put that in.

Of course, your implementation is not really C without expression handling in
the preprocessor.  You'll probably want to add it some day.

>Also, what exactly is a #pragma?  An example would help.

Examples:    #pragma listing
	     #pragma used-heavily(i, j, r)

If you just ignore all #pragma lines you'll be fine.  If you just abort at any
#pragma line, well, people differ on whether or not that's ok.

ajr