Você deve configurar a variável de ambiente KDE_DEBUG (para 1 ou qualquer outro valor).
Para restaurar o Dr. Konqi, remova a variável de ambiente KDE_DEBUG.
Edite o arquivo $KDEHOME/share/config/drkonqirc e adicione o seguinte:
Um core file é uma imagem da memória no momento em que sua aplicação quebrou. Utilizando este arquivo, você pode determinar quais variáveis estavam configuradas e em que ponto a aplicação quebrou.
Algumas distribuições desativam a produção de core files. Para ativa-los novamente, utilize o comando
ulimit -c unlimited.
Após obter o core file de um crash, você pode examina-lo com o comando gdb nomeapp core. Isso fará o gdb abrir o core file para a aplicação fornecida. Um vez no prompt do gdb, o comando mais útil é
bt, que produz um backtrace do crash.
Para mais informações sobre o uso do gdb, veja esta página
Check this page and kdesdk, there are a bunch of useful scripts there.
Check out kdesdk, and add this line to your ~/.gdbinit :
Then in gdb you can do
printqstring myqstring to see its contents.
QString myqstring = QString::fromLatin1("contents"); can be examined using
(gdb) printqstring myqstring $1 = "content"
Veja o arquivo kde-devel-gdb para descobrir outras macros definidas.
You must stop just after the main to load the debugging symbols of the shared library. After that, you can debug normally. One can go as far as creating a gdb macro, to stop right after the part was loaded. For kword, by example, I use:
define startkword break main run break 'KoDocument::KoDocument(int, QWidget *, char const *, QObject *, char const *, bool)' cont
Here are some steps that you can use to troubleshoot why your signal/slot connection is not working (your slot does not get called for some reason).
1) Verify that the connect() doesn't print a warning to the console at runtime.
If it does, check that you wrote Q_OBJECT, that the parameter names are not in the connect, that the parameter types are compatible, and that the slot is defined, and that the moc was compiled.
1b) Or you can just check to see what connect() returns as a bool. Although this won't give you the error message. 2) Verify that the signal is indeed emitted 3) Verify that the receiver isn't already deleted at that time 4) Verify that emitter->signalsBlocked() returns false
Yes, you must use kDebug():
#include <kdebug.h> kDebug() << "KMyApp just started";
The syntax is much like cout, you can use many native types between the "<<". This will print out a debugging message, which will automatically be turned off at release time (by --disable-debug). In case you want the message to still be there during releases, because it's a warning or an error, use kWarning() or kError().
Components and libraries are advised to use a debug area number, as in kDebug(1234). For this, the number must be registered in kdelibs/kdecore/kdebug.areas. Debug areas make it possible to turn off or on the debug output for specific area numbers, using the kdebugdialog program, which is part of kdebase. kdebugdialog --fullmode also permits to control where to log debug output. It is usually not necessary to register area numbers for standalone applications, unless it's so complex that you want to divide the output into several areas.
It is possible to omit the debug area number when calling kDebug by adding the following code to your top-level CMakeLists.txt:
For more information, about this, see Allen Winter's blog post.
To make it clear: do NOT use qDebug(), this one does not get disabled at releases. Also avoid using assert() or kFatal() which lead to a crash when something goes wrong and that is not a nice experience for the user. Better detect the error, output a kWarning() or kError(), and recover if possible.
To get timestamps with your debug output, which are useful for debugging multi-threaded, networked and asynchronous operations, export KDE_DEBUG_TIMESTAMP=1 before running your app. Since KDE SC 4.5.