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 Forums >>  Debuggers  >>  PyDBG, threads that don't like to be single stepped?

Topic created on: February 22, 2012 21:39 CST by nomnom .

Hey everyone, I've got a question about using PyDBG. I'm trying to debug the latest VLC, and everything works just fine if I do a simple thing like :

dbg = pydbg()
dbg.load("vlc.exe")
dbg.run()

Now, the problem is if I set new threads to single_step(True), the program will basically hang at a certain point. And it's not at the first thread or anything, it's later in the program, roughly 5 threads in. The only change I make is :

def handle_new_thread(dbg):
    dbg.single_step(True)
    return DBG_CONTINUE

def handle_single_step(dbg):
    dbg.single_step(True)
    return DBG_CONTINUE

...

dbg.set_callback(EXCEPTION_SINGLE_STEP,     handle_single_step)
dbg.set_callback(CREATE_THREAD_DEBUG_EVENT, handle_new_thread)

And this will work on some programs, but on some (like VLC 2.0) in this instance, it will just hang at some point. The question is, any ideas why setting a thread to single step would cause an issue?

Thanks for the help, it's much appreciated.

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