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package IO::Capture::ErrorMessages;
use Carp;
use base qw/IO::Capture/;
use IO::Capture::Tie_STDx;
sub _start {
my $self = shift;
$self->line_pointer(1);
$SIG{__WARN__} = sub {print STDERR @_;};
tie *STDERR, "IO::Capture::Tie_STDx";
}
sub _retrieve_captured_text {
my $self = shift;
my $messages = \@{$self->{'IO::Capture::messages'}};
@$messages = <STDERR>;
return 1;
}
sub _check_pre_conditions {
my $self = shift;
return unless $self->SUPER::_check_pre_conditions;
if (tied *STDERR) {
# if SIG{__WARN__} is already captured, this carp isn't seen until
# you read the capture that holds it
carp "WARNING: STDERR already tied, unable to capture";
return;
}
return 1;
}
sub _stop {
my $self = shift;
untie *STDERR;
$SIG{__WARN__} = $self->{'IO::Capture::handler_save'};
return 1;
}
1;
=head1 NAME
C<IO::Capture::ErrorMessages> - Capture output from C<STDERR> and C<warn()>
=head1 SYNOPSYS
# Generic example (Just to give the overall view)
use IO::Capture::Stderr;
my $capture = IO::Capture::ErrorMessages->new();
$capture->start();
print STDERR "Test Line One\n";
print STDERR "Test Line Two\n";
print STDERR "Test Line Three\n";
warn "Test line Four\n";
printf STDERR ("Test Line %08d\n", 5);
$capture->stop();
$line = $capture->read;
print "$line"; # prints "Test Line One"
$line = $capture->read;
print "$line"; # prints "Test Line Two"
$capture->line_pointer(4);
$line = $capture->read;
print "$line"; # prints "Test Line Four"
$current_line_position = $capture->line_pointer;
# More useful example 1 - "Using in module tests"
# Note: If you don't want to make users install
# the IO::Capture module just for your tests,
# you can just install in the t/lib directory
# of your module and use the lib pragma in
# your tests.
use lib "t/lib";
use IO::Capture::ErrorMessages;
use Test::More;
my $capture = IO::Capture::ErrorMessages->new;
$capture->start
# execute with a bad parameter to make sure get
# an error.
ok( ! $test("Bad Parameter") );
$capture->stop();
# More useful example 2 - "Use with GUI like Tk"
# If you are calling a CPAN module that may
# print some messages that you don't want going
# to the shell window, or being lost, you can
# capture them and then put to a log file or
# print in a text frame
=head1 DESCRIPTION
The module C<IO::Capture::Stderr>, is derived from the abstract class in
C<IO::Capture>. L<IO::Capture> It captures all output sent to STDERR
and installs a signal handler to capture the output sent via the
C<warn()> function (and friends - such as C<carp()>). We primarily use
it in module tests, where the test will cause some warning to be printed.
To keep the output from cluttering up the nice neat row of 'ok's. ;-)
Note: This module won't work with the perl function, C<system()>, or any
other operation involing a C<fork()>. If you want to capture the output
from a system command, it is faster to use C<open()> or backticks.
my $output = `/usr/sbin/ls -l 2>&1`;
=head1 METHODS
=head1 AUTHORS
Mark Reynolds
reynolds@sgi.com
Jon Morgan
jmorgan@sgi.com
=head1 COPYRIGHT
Copyright (c) 2003, Mark Reynolds and Jon Morgan. All Rights Reserved.
This module is free software. It may be used, redistributed and/or
modified under the same terms as Perl itself.
=cut
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