From: broeker AT acp3bf DOT knirsch DOT de (Hans-Bernhard Broeker)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: 1 trigraph(s) encountered ???
Date: 1 Oct 1999 15:15:05 +0200
Organization: RWTH Aachen, III. physikalisches Institut B
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Clemens Valens (c DOT valensNOc DOT SPAM AT mindless DOT com DOT invalid) wrote:
> When I compile a program with the -ansi option I get the
> message:

> 1 trigraph(s) encountered

> What does that mean? 

A 'trigraph' is a three-character sequence standing as a replacement
for a fourth character. It's meant as a way to write C programs in
some exotic environments, where not all the characters used by the C
programming language can be displayed or typed. The trigraph sequences
start with "??", and they are available *everywhere* in a C program,
including inside string constants. The latter fact turns the
originally valid idea into a stupid nuisance, which is why the GNU
folks don't like it at all, and warn you about it. To quote the 
gcc documentation:

`-trigraphs'
     Support ANSI C trigraphs.  You don't want to know about this
     brain-damage.  The `-ansi' option implies `-trigraphs'.

The typical effect will be that in some string that contains the "??"
sequence, it will have been replaced by some other letter. Search your
source for this string, to find where this problem occurs.

-- 
Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
Even if all the snow were burnt, ashes would remain.