[Freeciv-Dev] Re: Valgrind

["John Bauman" <john@xxxxxxxxxxxxxxxx>]

----- Original Message ----- 
From: "Jason Dorje Short" <jdorje@xxxxxxxxxxxx>
To: "Christian Knoke" <chrisk@xxxxxxxxx>; "Freeciv-Dev" 
<freeciv-dev@xxxxxxxxxxx>
Sent: Saturday, November 20, 2004 12:56 PM
Subject: [Freeciv-Dev] Re: Valgrind


> Christian Knoke wrote:
> > I just discovered valgrind.
> >
> > Is the output of valgrind of any interest, and when?
> Leak reports from valgrind are interesting.  You have to give --leak-check=yes 
> on the command line.  I've done this from time to time with the server, but 
> because valgrind is so slow I don't take the game past -3000 or so.  Running 
> it with either server or client under a more vigorous game would probably give 
> some good output.  But it would take a long time.
> Any valgrind warning is potentially useful.  The problem is valgrind gives 
> lots of warnings in libraries (particularly libgtk, gettext, and libreadline). 
> These are probably actually errors in those libraries but I don't know what to 
> do about them.  But once I discovered a bug in zlib this way (which they 
> fixed).  Any warning it gives you that comes from Freeciv code is surely of 
> interest and should be reported in its own separate ticket.
> Another common problem Valgrind reports is "Uninitialized data in write() 
> call".  This happens in the network code.  If we leave any packet fields 
> unitialized when sending a packet this will happen, but the valgrind backtrace 
> generally isn't useful to help us find it. Nonetheless it is a problem and 
> should be reported.
> Generally you should always run valgrind with --num-callers=50 to make sure 
> you get a sufficiently long backtrace.
> Valgrind has a method of suppressing certain types of warnings.  If someone 
> figured out how this worked we could probably make a Freeciv suppression file 
> that would ignore the warnings we don't care about.
A valgrind HOWTO ( http://electra.lbl.gov/ATLAS/valgrind_HOWTO.html ) says that 
you can have valgrind create its own suppression file by using the 
"--gen-suppressions=yes" option.  I don't have valgrind installed, but that 
seems to be worth a shot.
> jason