From: Nate Eldredge <neldredge AT hmc DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: problem with math.h
Date: 04 Oct 2000 23:28:57 -0700
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Michael Powe <michael+netscape AT trollope DOT org> writes:

> Hi,
> 
> I have a little something peculiar here.  I #included math.h in order to
> use the PI macro.  However, compiling with 
> 
> gcc -Wall -ansi -pedantic ... -lm 
> 
> results in an error that `PI' is undeclared.  I can get rid of this
> error and get gcc to compile the program by removing -ansi -pedantic
> from the command line.
> 
> Looking in math.h, I see that the section in which PI is #defined is
> preceded by #ifndef __STRICT_ANSI__ and #ifndef _POSIX_SOURCE.  
> 
> Does ANSI C exclude a value for PI?  Is there some reason why the
> standard library should not provide one?

The standard name is M_PI.  Use that instead, and you should be fully
ANSI compliant.

-- 

Nate Eldredge
neldredge AT hmc DOT edu