.\" Automatically generated by Pod::Man 4.09 (Pod::Simple 3.35) .\" .\" 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 .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . 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 .. .if !\nF .nr F 0 .if \nF>0 \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} .\} .\" ======================================================================== .\" .IX Title "Class::ErrorHandler 3pm" .TH Class::ErrorHandler 3pm "2017-08-06" "perl v5.26.0" "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" Class::ErrorHandler \- Base class for error handling .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 2 \& package Foo; \& use base qw( Class::ErrorHandler ); \& \& sub class_method { \& my $class = shift; \& ... \& return $class\->error("Help!") \& unless $continue; \& } \& \& sub object_method { \& my $obj = shift; \& ... \& return $obj\->error("I am no more") \& unless $continue; \& } \& \& package main; \& use Foo; \& \& Foo\->class_method or die Foo\->errstr; \& \& my $foo = Foo\->new; \& $foo\->object_method or die $foo\->errstr; .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" \&\fIClass::ErrorHandler\fR provides an error-handling mechanism that's generic enough to be used as the base class for a variety of \s-1OO\s0 classes. Subclasses inherit its two error-handling methods, \fIerror\fR and \fIerrstr\fR, to communicate error messages back to the calling program. .PP On failure (for whatever reason), a subclass should call \fIerror\fR and return to the caller; \fIerror\fR itself sets the error message internally, then returns \f(CW\*(C`undef\*(C'\fR. This has the effect of the method that failed returning \&\f(CW\*(C`undef\*(C'\fR to the caller. The caller should check for errors by checking for a return value of \f(CW\*(C`undef\*(C'\fR, and calling \fIerrstr\fR to get the value of the error message on an error. .PP As demonstrated in the \s-1SYNOPSIS\s0, \fIerror\fR and \fIerrstr\fR work as both class methods and object methods. .SH "USAGE" .IX Header "USAGE" .SS "Class\->error($message)" .IX Subsection "Class->error($message)" .ie n .SS "$object\->error($message)" .el .SS "\f(CW$object\fP\->error($message)" .IX Subsection "$object->error($message)" Sets the error message for either the class \fIClass\fR or the object \&\fI\f(CI$object\fI\fR to the message \fI\f(CI$message\fI\fR. Returns \f(CW\*(C`undef\*(C'\fR. .SS "Class\->errstr" .IX Subsection "Class->errstr" .ie n .SS "$object\->errstr" .el .SS "\f(CW$object\fP\->errstr" .IX Subsection "$object->errstr" Accesses the last error message set in the class \fIClass\fR or the object \fI\f(CI$object\fI\fR, respectively, and returns that error message. .SH "LICENSE" .IX Header "LICENSE" This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. .SH "AUTHOR & COPYRIGHT" .IX Header "AUTHOR & COPYRIGHT" Except where otherwise noted, \fIClass::ErrorHandler\fR is Copyright 2004 Benjamin Trott, cpan@stupidfool.org. All rights reserved.