|
|
Jukebox Power Pack 1.0 (Default branch)
01-24-2008
The Jukebox Power Pack is the result of acollaboration between the aTunes, Jajuk, and Jukesaudio player projects. It contains the threeapplications bundled together. It includes thealbum Kogani by Suerte. It is able to run on allJava 6-ready platforms.|
|
Carp::Clan(3) User Contributed Perl Documentation Carp::Clan(3) NAME
Carp::Clan - Report errors from perspective of caller of a "clan" of modules 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 qw(^MyClan::); croak "We're outta here!"; use Carp::Clan; 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", "Pack::B" and so on, and each of them uses ""Carp::Clan 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", and module "Pack::A" calls module "Pack::B", an exception raised in module "Pack::B" will appear to have originated in "tool.pl" where "Pack::A" was called, and not in "Pack::A" where "Pack::B" was called, as the unmodified ""Carp.pm"" would try to make you believe ":-)". This works similarly if "Pack::B" calls "Pack::C" where the exception is raised, etcetera. 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"", 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;"" 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"" 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" to a true value. You would typically enable it by saying use Carp::Clan 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"" 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. perl v5.12.1 2009-10-24 Carp::Clan(3)