.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "Carp::Clan 3" .TH Carp::Clan 3 2023-07-25 "perl v5.38.0" "User Contributed Perl Documentation" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH NAME Carp::Clan \- Report errors from perspective of caller of a "clan" of modules .SH VERSION .IX Header "VERSION" version 6.08 .SH SYNOPSIS .IX Header "SYNOPSIS" .Vb 1 \& 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\*(Aqre outta here!"; \& \& use Carp::Clan; \& confess "This is how we got here!"; .Ve .SH DESCRIPTION .IX Header "DESCRIPTION" This module is based on "\f(CW\*(C`Carp.pm\*(C'\fR" from Perl 5.005_03. It has been modified to skip all package names matching the pattern given in the "use" statement inside the "\f(CWqw()\fR" term (or argument list). .PP Suppose you have a family of modules or classes named "Pack::A", "Pack::B" and so on, and each of them uses "\f(CW\*(C`Carp::Clan qw(^Pack::);\*(C'\fR" (or at least the one in which the error or warning gets raised). .PP 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 "\f(CW\*(C`Carp.pm\*(C'\fR" would try to make you believe \f(CW\*(C`:\-)\*(C'\fR. .PP This works similarly if "Pack::B" calls "Pack::C" where the exception is raised, et cetera. .PP In other words, this blames all errors in the "\f(CW\*(C`Pack::*\*(C'\fR" modules on the user of these modules, i.e., on you. \f(CW\*(C`;\-)\*(C'\fR .PP 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 \f(CW@ISA\fR \&\- as in the original "\f(CW\*(C`Carp.pm\*(C'\fR" module \- doesn't help). .PP 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. .PP In case you just want to ward off all error messages from the module in which you "\f(CW\*(C`use Carp::Clan\*(C'\fR", 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 "\f(CW\*(C`use Carp;\*(C'\fR" for \f(CW\*(C`;\-)\*(C'\fR), 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. .PP I.e., just "\f(CW\*(C`use Carp::Clan;\*(C'\fR" without any arguments and call "carp" or "croak" as appropriate, and they will automatically defend your module against all blames! .PP 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. .SS "Forcing a Stack Trace" .IX Subsection "Forcing a Stack Trace" As a debugging aid, you can force "\f(CW\*(C`Carp::Clan\*(C'\fR" 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. .PP This feature is enabled either by "importing" the non-existent symbol \&'verbose', or by setting the global variable "\f(CW$Carp::Clan::Verbose\fR" to a true value. .PP You would typically enable it by saying .PP .Vb 1 \& use Carp::Clan qw(verbose); .Ve .PP Note that you can both specify a "family pattern" and the string "verbose" inside the "\f(CWqw()\fR" 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. .SH BUGS .IX Header "BUGS" The "\f(CW\*(C`Carp::Clan\*(C'\fR" routines don't handle exception objects currently. If called with a first argument that is a reference, they simply call "\f(CWdie()\fR" or "\f(CWwarn()\fR", as appropriate. .PP Bugs may be submitted through the RT bug tracker (or bug\-Carp\-Clan@rt.cpan.org ). .SH AUTHOR .IX Header "AUTHOR" Steffen Beyer .SH CONTRIBUTORS .IX Header "CONTRIBUTORS" .IP \(bu 4 Karen Etheridge .IP \(bu 4 Joshua ben Jore .IP \(bu 4 Kent Fredric .SH "COPYRIGHT AND LICENSE" .IX Header "COPYRIGHT AND LICENSE" This software is copyright (c) 2001 by Steffen Beyer, Joshua ben Jore. .PP This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.