From Forum Nokia Wiki

One painful experience when developing a Symbian C++ application is that the start up speed of the emulator is rather slow. Even with a modern powerful CPU, we still waste a lot of time in the circle (1) "editing source"... (2) "set breakpoints"... (3) "build"... (4) "START EMULATOR"... (5) "start application"... (6) "check variable values"... (7) "close/crash emulator"... (8) "editing source"...

ESPECIALLY STEP 4!

In the CodeWarrior IDE there is a feature for debugging on the fly. With this feature, we can change the circle into something like this (1) "START EMULATOR"... (2) "editing source"... (3) "set breakpoints"... (4) "build"... (5) "start application in emulator"... (6) "check variable values"... (7) "close application in emulator"... (8) "re-edit source" and so on.

Got the trick? Yes, only one "START EMULATOR" step is needed, which means you could save a lot of time while debugging with emulator.

Nokia has since created Carbide.c++ to replace CodeWarrior. This feature is on the list of "Emulator features", but not "IDE features" as previously. Just enable the "Just-In-Time Debugging" in the emulator's configuration option window. Then you will get this feature.

The reason that the name of this article is not "Just-In-Time debugging" is that many people would have no idea of what this word means.

Refer to this link for more Tips

Debugging Tips and Tricks