bootstrap/3653: -fmessage-length=72 with g++ makes no sense

[Enrico Scholz]

The following reply was made to PR bootstrap/3653; it has been noted by GNATS.

From: Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
To: Gabriel Dos Reis <Gabriel.Dos-Reis@cmla.ens-cachan.fr>
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: bootstrap/3653: -fmessage-length=72 with g++ makes no sense
Date: 12 Jul 2001 13:02:21 +0200

 Gabriel Dos Reis <Gabriel.Dos-Reis@cmla.ens-cachan.fr> writes:
 
 > | 1. It breaks existing tools. E.g. Emacs awaits a "<location>:<line>
 > | <error-msg>" format and gets confused by the current behavior
 > 
 > My personnal experience (yes, I write and compile my work under Emacs)
 > doesn't match your report.  It just works fine.
 
 Emacs detects errors only if they have the format described above. The
 wrapped lines are plain text for it and won't be recognized as a part of
 diagnostic. Try to move the mouse over wrapped and unwrapped
 error-messages! The whole unwrapped message will be marked (which helps
 to increase readability), but only the first line of the wrapped one.
 
 Besides the misinterpretation by tools, the wrapped output is more
 difficulty to read by humans also:
 
 - the human brain can surveying grouped data faster than ungrouped
   one. The current wrapping destroys grouping.
 
 - the count of lines per errormessage is increased by a factor of 3 or
   more in most cases where templates are involved. Therefore messages
   belonging together (e.g. naming of possible candidates) can not be
   read at a glance and I have to scroll the compilation-buffer manually.
 
  
 > [... value for -fmessage-length=X ...]
 > We've through that debate over and over in the past.  The default
 > value was what contented the majority which expressed their voices.
 > The exact value is configurable.
 
 I suggest a value of `0'. ;) ... at least if it is not a tty...
 
 
 > [...]
 > If you don't want the fonctionality, the documentation says you can
 > specify -fmessage-length=0
 
 Older gcc do not know this option and will fail to compile. Therefore it
 does not exist a simple way to gain unwrapped messages with gcc.
 
 I think that backward-compatibility should be preserved in this case,
 because line-wrapping offers only a few advantages but has some drawbacks,
 
 
 
 
 
 Enrico