# Carp::Clan - Report errors from perspective of caller of a "clan" o... - perldoc - [phpMan] ## NAME [Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown) - Report errors from perspective of caller of a "clan" of modules ## VERSION version 6.08 ## SYNOPSIS carp - warn of errors (from perspective of caller) cluck - warn of errors with stack backtrace croak - die of errors (from perspective of caller) confess - die of errors with stack backtrace use [Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown) qw(^MyClan::); croak "We're outta here!"; use [Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown); confess "This is how we got here!"; ## DESCRIPTION This module is based on ""Carp.pm"" from Perl 5.005_03. It has been modified to skip all package names matching the pattern given in the "use" statement inside the "qw()" term (or argument list). Suppose you have a family of modules or classes named "[Pack::A](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AA/markdown)", "[Pack::B](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AB/markdown)" and so on, and each of them uses ""[Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown) qw(^Pack::);"" (or at least the one in which the error or warning gets raised). Thus when for example your script "tool.pl" calls module "[Pack::A](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AA/markdown)", and module "[Pack::A](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AA/markdown)" calls module "[Pack::B](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AB/markdown)", an exception raised in module "[Pack::B](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AB/markdown)" will appear to have originated in "tool.pl" where "[Pack::A](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AA/markdown)" was called, and not in "[Pack::A](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AA/markdown)" where "[Pack::B](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AB/markdown)" was called, as the unmodified ""Carp.pm"" would try to make you believe ":-)". This works similarly if "[Pack::B](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AB/markdown)" calls "[Pack::C](https://www.chedong.com/phpMan.php/perldoc/Pack%3A%3AC/markdown)" where the exception is raised, et cetera. In other words, this blames all errors in the ""Pack::*"" modules on the user of these modules, i.e., on you. ";-)" The skipping of a clan (or family) of packages according to a pattern describing its members is necessary in cases where these modules are not classes derived from each other (and thus when examining @ISA - as in the original ""Carp.pm"" module - doesn't help). The purpose and advantage of this is that a "clan" of modules can work together (and call each other) and throw exceptions at various depths down the calling hierarchy and still appear as a monolithic block (as though they were a single module) from the perspective of the caller. In case you just want to ward off all error messages from the module in which you ""use [Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown)"", i.e., if you want to make all error messages or warnings to appear to originate from where your module was called (this is what you usually used to ""use Carp;"" for ";-)"), instead of in your module itself (which is what you can do with a "die" or "warn" anyway), you do not need to provide a pattern, the module will automatically provide the correct one for you. I.e., just ""use [Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown);"" without any arguments and call "carp" or "croak" as appropriate, and they will automatically defend your module against all blames! In other words, a pattern is only necessary if you want to make several modules (more than one) work together and appear as though they were only one. ### Forcing a Stack Trace As a debugging aid, you can force ""[Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown)"" to treat a "croak" as a "confess" and a "carp" as a "cluck". In other words, force a detailed stack trace to be given. This can be very helpful when trying to understand why, or from where, a warning or error is being generated. This feature is enabled either by "importing" the non-existent symbol 'verbose', or by setting the global variable "$[Carp::Clan::Verbose](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan%3A%3AVerbose/markdown)" to a true value. You would typically enable it by saying use [Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown) qw(verbose); Note that you can both specify a "family pattern" and the string "verbose" inside the "qw()" term (or argument list) of the "use" statement, but consider that a pattern of packages to skip is pointless when "verbose" causes a full stack trace anyway. ## BUGS The ""[Carp::Clan](https://www.chedong.com/phpMan.php/perldoc/Carp%3A%3AClan/markdown)"" routines don't handle exception objects currently. If called with a first argument that is a reference, they simply call "die()" or "warn()", as appropriate. Bugs may be submitted through the RT bug tracker <> (or >). ## AUTHOR Steffen Beyer <> ## CONTRIBUTORS * Karen Etheridge <> * Joshua ben Jore <> * Kent Fredric <> ## COPYRIGHT AND LICENSE This software is copyright (c) 2001 by Steffen Beyer, Joshua ben Jore. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.