TraceMessages(3) User Contributed Perl Documentation TraceMessages(3)NAMELog::TraceMessages - Perl extension for trace messages used in
debugging
SYNOPSIS
use Log::TraceMessages qw(t d);
$Log::TraceMessages::On = 1;
t 'got to here';
t 'value of $a is ' . d($a);
{
local $Log::TraceMessages::On = 0;
t 'this message will not be printed';
}
$Log::TraceMessages::Logfile = 'log.out';
t 'this message will go to the file log.out';
$Log::TraceMessages::Logfile = undef;
t 'and this message is on stderr as usual';
# For a CGI program producing HTML
$Log::TraceMessages::CGI = 1;
# Or to turn on trace if there's a command-line argument '--trace'
Log::TraceMessages::check_argv();
DESCRIPTION
This module is a slightly better way to put trace statements into your
code than just calling print(). It provides an easy way to turn trace
on and off for particular sections of code without having to comment
out bits of source.
USAGE
$Log::TraceMessages::On
Flag controlling whether tracing is on or off. You can set it as
you wish, and of course it can be "local"-ized. The default is
off.
$Log::TraceMessages::Logfile
The name of the file to which trace should be appended. If this is
undefined (which is the default), then trace will be written to
stderr, or to stdout if $CGI is set.
$Log::TraceMessages::CGI
Flag controlling whether the program printing trace messages is a
CGI program (default is no). This means that trace messages will
be printed as HTML. Unless $Logfile is also set, messages will be
printed to stdout so they appear in the output page.
t(messages)
Print the given strings, if tracing is enabled. Unless $CGI is
true or $Logfile is set, each message will be printed to stderr
with a newline appended.
trace(messages)
Synonym for "t(messages)".
d(scalar)
Return a string representation of a scalar's value suitable for use
in a trace statement. This is just a wrapper for Data::Dumper.
"d()" will exit with '' if trace is not turned on. This is to stop
your program being slowed down by generating lots of strings for
trace statements that are never printed.
dmp(scalar)
Synonym for "d(scalar)".
check_argv()
Looks at the global @ARGV of command-line parameters to find one
called '--trace'. If this is found, it will be removed from @ARGV
and tracing will be turned on. Since tracing is off by default,
calling "check_argv()" is a way to make your program print trace
only when you ask for it from the command line.
AUTHOR
Ed Avis, ed@membled.com
SEE ALSOperl(1), Data::Dumper(3).
POD ERRORS
Hey! The above document had some coding errors, which are explained
below:
Around line 218:
You forgot a '=back' before '=head1'
perl v5.14.1 2003-12-05 TraceMessages(3)
