Re: Bug in GLib, libglade, libc??

[Fabricio Rocha <rocha_fabricio yahoo com br>]

Thank you very much, Yeti and Samuel, for your replies!

	I really believe that there is something wrong in MY code, and not in 
libglade, nor libc, nor GTK, etc., that makes my program react so 
different every time I compile and run it. However, I still could not 
figure what exactly is wrong.

	I have a suspicion from my lack of practice in C: a module of my 
program uses a structured type which must contain, as its last member, a 
dynamic list of strings, i.e., pointers to gchars (**list). Sometimes I 
need to fill only the first string, and sometimes I will need more than 
one string. So I suspect that each attempt to set a value for one of 
these pointers cause a serious corruption of other areas of the program, 
like the GTK stuff in memory. I have tried to assign values to this 
(these) pointers both with g_strdup and by creating a local, initialized 
array and assigning its address to the pointer. Neither worked. Do you 
think I should give each pointer a malloc'd space somewhere in memory, 
and then strcpy the value to this pointer?

	By the way, I have read a lot of GDB and Valgrind docs, and still could 
not get anything from them. My application is one of those standard 
libglade apps with a main() function that only loads a main window from 
the XML and show it, and I really don´t understand some things from 
Valgrind:

	- "Conditional jump or move depends on uninitialised values", which is 
by itself not so bad, according to Valgrind docs;

	- "Syscall param write (buf) points to uninitialised byte(s)" in the 
lines which calls gtk_init(&argc, &argv) and gtk_init(); which, if I am 
right, is normal as there is nothing passed to the application in the 
command line;

	- Various "Invalid read of size 4 (...) Address 0xxxxx is 24 bytes 
inside a block of size 25 alloc´d" caused by the line with 
"glade_xml_signal_autoconnect". Hey, what is wrong if an address is 
WITHIN the alloc´d block?? And look that, until now, there is *not* code 
of "myself", it is just what every libglade example tells!

	- "Invalid free() / delete / delete[]" in the lines right after 
gtk_main(), where I try to g_free both the pointers to the loaded XML 
file and the main window widget. I have set breakpoints in GDB right 
before these lines and they HAD non-NULL values until here...

	- The program finishes with surprising 141kB "possibly lost" and 931kB 
(!) "still reachable" memory leaks. I can´t figure out what exactly is 
causing such a memory waste -- the only thing the program does until now 
is loading and closing the main window and a dialog window! In 
GTK/libglade programming, could you point out which are the most common 
"to-check" things to avoid that?

	Please, sorry for such a big post, but I hope you understand that, as 
Yeti said, I am really *trying* to debug the thing by myself, instead of 
just coming here and shout.... but until now I couldn´t really find any 
big clue with GDB, and, although Valgrind is really impressive, it does 
not tell much about *what* to do for newbies like me -- as a friend 
said, it is like going to a physician who says "hmm, it looks like you 
have fluid in your left lung", but does not tell you how it happened and 
what to do then...

Thank you again and best regards to all!

Fabricio Rocha
Brasilia, Brasil

        
        
                
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