[Freeciv-Dev] Re: Valgrind

[Jason Dorje Short <jdorje@xxxxxxxxxxxx>]

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.
jason