[erlang-questions] Tracing a call sequence

[Lennart Ohman]

Hi, return_trace() can only be used in the fun2ms and that can
only be done in the shell. It is short for the match_spec
[{'_',[],[{return_trace}]}]

> > dbg:tpl( mnesia_meter, dbg:fun2ms(fun(_) -> return_trace() end)).

So if you want to write a program you shall write

dbg:tpl(TheModule,'_','_',[{'_',[],[{return_trace}]}])

Note that this will only give you trace on all functions in
TheModule. If execution takes a detour in another module, you
must add that module too and repeat your test. And to know
which modules you must trace you must read the code.

Best Regards
Lennart

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> -----Original Message-----
> From: erlang-questions-bounces@REDACTED [mailto:erlang-questions-
> bounces@REDACTED] On Behalf Of Joel Reymont
> Sent: Sunday, June 10, 2007 8:01 PM
> To: Bengt Kleberg
> Cc: Erlang Questions
> Subject: Re: [erlang-questions] Tracing a call sequence
> 
> Where does return_trace/0 come from?
> 
> It works at the erl prompt but I get an error on return_trace when
> trying to compile my module.
> 
> ./foo.erl:43: function return_trace/0 undefined
> 
>      Thanks, Joel
> 
> On Jun 10, 2007, at 5:21 PM, Bengt Kleberg wrote:
> 
> > dbg:tracer().
> >
> > dbg:p( all, [call] ).
> >
> > dbg:tpl( mnesia_meter, dbg:fun2ms(fun(_) -> return_trace() end)).
> 
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