[erlang-questions] compiling erlang

Ulf Wiger <>
Tue Apr 27 21:04:33 CEST 2010

Wes James wrote:
> I'm noticing a lot of "erlc -W  +debug_info" during the "make" phase
> of erlang.  Is debug info being generated for all of erlang - if so,
> won't this make erlang slower?

No. Debug_info is stored in the beam file and can be retrieved using
the function beam_lib:chunks(BeamFile, [abstract_code]). It is
ignored by the code loader and has no effect on the runtime behaviour.

Debug_info can be used by offline analysis tools, such as dialyzer,
and also by runtime analysis tools like cover, which reads the
debug_info, instruments the code, compiles it and loads it, replacing
the original module.

Ulf W

Ulf Wiger
CTO, Erlang Solutions Ltd, formerly Erlang Training & Consulting Ltd



Since January 1st 2010 Erlang Training and Consulting Ltd. has become ERLANG SOLUTIONS LTD.


More information about the erlang-questions mailing list