[gcompris-devel] problem compiling gcomprixogoo

[Bill Bogstad]

I've been trying to compile various versions of gcompris under Ubuntu
8.04 off and on for a while now.  I've been able to compile 8.4.12
successfully, but I've ran into a problem with the current head of
gcomprixogoo:

commit 10f0529c02b5d88a2e177860002135745ce04bbe
Author: Bruno Coudoin <bruno.coudoin at free.fr>
Date:   Mon Jul 13 15:01:09 2009 +0200

    Create the ChangeLog automatically from git log.

After dealing with a number of dependency issues, the compilation
eventually dies as follows:

..........
 gcc -DHAVE_CONFIG_H -I. -I../.. -I../../src -I../../intl
-I../../src/goocanvas/src -pthread -I/usr/include/gtk-2.0
-I/usr/lib/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo
-I/usr/include/pango-1.0 -I/usr/include/glib-2.0
-I/usr/lib/glib-2.0/include -I/usr/include/freetype2
-I/usr/include/libpng12 -I/usr/include/pixman-1
-I/usr/include/gstreamer-0.10 -I/usr/include/libxml2
-I/usr/include/librsvg-2 -I/usr/include/libxml2 -g -O2 -Wall -Werror
-MT target.lo -MD -MP -MF .deps/target.Tpo -c target.c  -fPIC -DPIC -o
.libs/target.o
cc1: warnings being treated as errors
target.c: In function ‘animate_items’:
target.c:607: warning: ‘points’ may be used uninitialized in this function
target.c:607: note: ‘points’ was declared here
make[4]: *** [target.lo] Error 1
make[4]: Leaving directory
`/home/bogstad/software/gcompris/gcompris.git/src/target-activity'

I've taken a look at the code and I think the problem is actually
related to add_points().  A local variable points is created which
could be returned uninitialized if the diametre < targetDefinition is
always false.  GCC can't tell if this ever happens and assumes that
add_points returns a random value.  The thing is that add_points is
only called from animate_items which promptly discards the return
value of add_points anyway so in some sense it doesn't matter.  On the
other hand, the same code in 8.4.12 declares add_points() as void.
It's not clear why the change to return an unused value was made in
the source code in the first place.

Git blame seems seems to show the following:

c682a381 src/target-activity/target.c (Bruno Coudoin 2009-01-18
23:28:50 +0000 607) .....

as the commit that introduced the change.   Are there some pending
changes which will cause the return value of add_point() to matter?

In the meantime, can someone suggest how to change the configuration
system to not pass -Werror on the command line to gcc so it will
ignore (this apparently
spurious warning) rather then treat it as an error and exit.

Thanks,
Bill Bogstad