Re: Debugging multi-threaded programmes

[Fabian Scheler]

Hello Aref,

> Is there an extensive use of ddd over gdb for debugging multi-threaded
> applications, or in other words how reliable or easy is it to do this,
> especially for hard real time applications in Linux user space?

I would suppose this to be as stable as debugging threads with gdb and
I suppose that to work. Debugging real-time applications, however, is
another issue, as you have to be aware of the probe effect caused by
debuggers like gdb ...

> I have had a lot of difficulties doing this and I sincerely hope someone can
> help. I am having a range of problems with ddd version 3.3.11 on top of gdb
> version 6.3.0.0-1.122rh. The most annoying problem is local variables not
> known to the gdb - I get "No symbol "fred" in current context" although that
> may be a gdb problem. I have compiled my programme with:

Did you try 'Data'->'Display Local Variables' in the Menu. Normally
the compiler does not generate symbols for local variables (these
variables just exist on the stack) and so you cannot add a display for
them.

Besides that: I would not switch to -O0, gcc does not perform register
allocation with -O0 and so the code finally generated has nothing to
do with the real code that will actually be run. I would use compiler
switches as close as possible to the real ones.

Ciao, Fabian