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.\"
.IX Title "Agent::Tag::Callback 3pm"
.TH Agent::Tag::Callback 3pm "2016-09-17" "perl v5.22.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
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.nh
.SH "NAME"
Log::Agent::Tag::Callback \- a dynamic tag string
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\& require Log::Agent::Tag::Callback;
\& # Inherits from Log::Agent::Tag.
\&
\& my $tag = Log::Agent::Tag::Callback\->make(
\&     \-name      => "session id",
\&     \-callback  => Callback\->new($obj, \*(Aqmethod\*(Aq, @args),
\&     \-postfix   => 1,
\&     \-separator => " \-\- ",
\& );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This class represents a dynamic tag string, whose value is determined
by invoking a pre-determined callback, which is described by a \f(CW\*(C`Callback\*(C'\fR
object.
.PP
You need to make your application depend on the \f(CW\*(C`Callback\*(C'\fR module from \s-1CPAN\s0
if you make use of this tagging feature, since \f(CW\*(C`Log::Agent\*(C'\fR does not
depend on it, on purpose (it does not really use it, it only offers an
interface to plug it in).  At least version 1.02 must be used.
.SH "CREATION ROUTINE PARAMETERS"
.IX Header "CREATION ROUTINE PARAMETERS"
The following parameters are defined, in alphabetical order:
.ie n .IP """\-callback"" => ""Callback"" \fIobject\fR" 4
.el .IP "\f(CW\-callback\fR => \f(CWCallback\fR \fIobject\fR" 4
.IX Item "-callback => Callback object"
The callback to invoke to determine the value of the tag.  The call is
protected via a \fIbusy\fR flag, in case there is an unwanted recursion due
to a call to one of the logging routines whilst within the callback.
.Sp
If the callback is busy, the tag emitted is:
.Sp
.Vb 1
\&    callback "user" busy
.Ve
.Sp
assuming \f(CW\*(C`user\*(C'\fR is the name you supplied via \f(CW\*(C`\-name\*(C'\fR for this tag.
.ie n .IP """\-name"" => \fIname\fR" 4
.el .IP "\f(CW\-name\fR => \fIname\fR" 4
.IX Item "-name => name"
The name of this tag.  Used to flag a callback as \fIbusy\fR in case there is
an unwanted recursion into the callback routine.
.ie n .IP """\-postfix"" => \fIflag\fR" 4
.el .IP "\f(CW\-postfix\fR => \fIflag\fR" 4
.IX Item "-postfix => flag"
Whether tag should be placed after or before the log message.
By default, it is prepended to the log message, i.e. this parameter is false.
.ie n .IP """\-separator"" => \fIstring\fR" 4
.el .IP "\f(CW\-separator\fR => \fIstring\fR" 4
.IX Item "-separator => string"
The separation string between the tag and the log message.
A single space by default.
.SH "AUTHOR"
.IX Header "AUTHOR"
Raphael Manfredi \fI<Raphael_Manfredi@pobox.com>\fR
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fICallback\fR\|(3), \fILog::Agent::Tag\fR\|(3), \fILog::Agent::Message\fR\|(3).