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6 non-PAUSE users.

Graham Knop
and 1 contributors


Devel::Confess - Warns and dies noisily with stack backtraces


  use Devel::Confess;

makes every warn() and die() complains loudly in the calling package and elsewhere. Works even when exception objects are thrown. More often used on the command line:

  perl -MDevel::Confess script.pl

or as shorthand:

  perl -d:Confess script.pl


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. Unlike other similar modules (e.g. Carp::Always), it includes stack traces even when exception objects are thrown.

Here are how stack backtraces produced by this module looks:

  # it works for explicit die's and warn's
  $ perl -MDevel::Confess -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 -MDevel::Confess -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.

Stack traces are also included if raw non-object references are thrown.


import( @options )

Enables stack traces and sets options. Options can be prefixed with no_ to disable them.


Enable attaching stack traces to exception objects. Enabled by default.


Load the Devel::Confess::Builtin module to use built in stack traces on supported exception types. Disabled by default.


Dumps the contents of references in arguments in stack trace, instead of only showing their stringified version. Disabled by default.


Colorizes error messages in red and warnings in yellow. Disabled by default.


Includes a snippet of the source for each level of the stack trace. Disabled by default.

The default options can be changed by setting the DEVEL_CONFESS_OPTIONS environment variable to a space separated list of options.



Classes or roles added to this hash will not have stack traces attached to them. This is useful for exception classes that provide their own stack traces, or classes that don't cope well with being re-blessed. If Devel::Confess::Buildin is loaded, it will automatically add its supported exception types to this hash.

Default Entries:


Provides a stack trace


Provides a stack trace


The idea, part of the code, and most of the documentation are taken from Carp::Always.


Please report bugs via CPAN RT http://rt.cpan.org/NoAuth/Bugs.html?Dist=Devel-Confess.


This module uses several ugly tricks to do its work and surely has bugs.

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


  • Graham Knop, <haarg@haarg.org>

  • Adriano Ferreira, <ferreira@cpan.org>


None yet.


Copyright (c) 2005-2013 the "AUTHORS" and "CONTRIBUTORS" as listed above.


This library is free software and may be distributed under the same terms as perl itself. See http://dev.perl.org/licenses/.