Appender::Screen(3)

NAME
Log::Log4perl::Appender::Screen - Log to STDOUT/STDERR

SYNOPSIS
    use Log::Log4perl::Appender::Screen;

    my $app = Log::Log4perl::Appender::Screen->new(
      autoflush => 1,
      stderr    => 0,
      utf8      => 1,
    );

    $file->log(message => "Log me\n");

DESCRIPTION
This is a simple appender for writing to STDOUT or STDERR.

The constructor new() takes an optional parameter "stderr":

•   If set to a false value, it will log all levels to STDOUT (or, more accurately, whichever file handle is selected via select(), STDOUT by default).

•   If set to a hash, then any "log4p_level" with a truthy value will dynamically use STDERR, or STDOUT otherwise.

•   Otherwise, if a true value (the default setting is 1), messages will be logged to STDERR.

    # All messages/levels to STDERR
    my $app = Log::Log4perl::Appender::Screen->new(
        stderr  => 1,
    );

    # Only ERROR and FATAL to STDERR (case-sensitive)
    my $app = Log::Log4perl::Appender::Screen->new(
        stderr  => { ERROR => 1, FATAL => 1},
    );

Design and implementation of this module has been greatly inspired by Dave Rolsky's "Log::Dispatch" appender framework.

To enable printing wide utf8 characters, set the utf8 option to a true value:

    my $app = Log::Log4perl::Appender::Screen->new(
      stderr    => 1,
      utf8      => 1,
    );

This will issue the necessary binmode command to the selected output channel (stderr/stdout).

To enable autoflush, set the "autoflush" option to a true value:

    my $app = Log::Log4perl::Appender::Screen->new(
      autoflush => 1,
    );

This will issue the necessary autoflush command to the selected output channel (stderr/stdout).

This is required in containers, especially when the log volume is low, to not buffer the log messages and cause a significant delay.

LICENSE
Copyright 2002-2026 by Mike Schilli <m@perlmeister.com> and Kevin Goess <cpan@goess.org>.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.