Carp::Always - Warns and dies noisily with stack backtraces


  use Carp::Always;

makes every warn() and die() complains loudly in the calling package and elsewhere. More often used on the command line:

  perl -MCarp::Always


This module is meant as a debugging aid. It can be used to make a script complain loudly with stack backtraces when warn()ing or die()ing.

Here are how stack backtraces produced by this module looks:

  # it works for explicit die's and warn's
  $ perl -MCarp::Always -e 'sub f { die "arghh" }; sub g { f }; g'
  arghh at -e line 1
          main::f() called at -e line 1
          main::g() called at -e line 1

  # it works for interpreter-thrown failures
  $ perl -MCarp::Always -w -e 'sub f { $a = shift; @a = @$a };' \
                           -e 'sub g { f(undef) }; g'
  Use of uninitialized value in array dereference at -e line 1
          main::f('undef') called at -e line 2
          main::g() called at -e line 2

In the implementation, the Carp module does the heavy work, through longmess(). The actual implementation sets the signal hooks $SIG{__WARN__} and $SIG{__DIE__} to emit the stack backtraces.

Oh, by the way, carp and croak when requiring/using the Carp module are also made verbose, behaving like cluck and confess, respectively.


Nothing at all is exported.


This module was born as a reaction to a release of Acme::JavaTrace by Sébastien Aperghis-Tramoni. Sébastien also has a newer module called Devel::SimpleTrace with the same code and fewer flame comments on docs. The pruning of the uselessly long docs of this module were prodded by Michael Schwern.

Schwern and others told me "the module name stinked" - it was called Carp::Indeed. After thinking long and not getting nowhere, I went with nuffin's suggestion and now it is called Carp::Always. Carp::Indeed which is now deprecate lives in its own distribution (which won't go anywhere but will stay there as a redirection to this module).


Please report bugs via CPAN RT


Every (un)deserving module has its own pet bugs.

  • This module does not play well with other modules which fusses around with warn, die, $SIG{'__WARN__'}, $SIG{'__DIE__'}.

  • Test scripts are good. I should write more of these.

  • I don't know if this module name is still a bug as it was at the time of Carp::Indeed.


Adriano Ferreira, <>


Copyright (C) 2005-2013 by Adriano R. Ferreira

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.