Retrieving Error Messages

TStanley has asked for the wisdom of the Perl Monks concerning the following question:

I am attempting to use the Simran::Log::Log and Simran::Error::Error modules, but am running into an interesting problem. The script I am testing with is as follows:

#!/opt/perl5/bin/perl -w
use strict;
use Simran::Log::Log;
use Simran::Error::Error;

my $x=5;my $y=4;
my $logfile="/home/tstanley/Logfile";
my $syslogger=Simran::Log::Log->new($logfile);
my $errlogger=Simran::Error::Error->new();
$errlogger->clear();

if($y<$x){
  $errlogger->set("Y is smaller than X");
  $syslogger->write("Y is smaller than X");
}

my @ERR=$errlogger->msg();
my $ERRMSG=$errlogger->msg();

print "Error is: @ERR\n";
print "Error is: $ERRMSG\n";

my $msg=$syslogger->error();
print "Message is $msg\n";
[download]

This generates a “use of an unitialized value in concatenation error” at line 25, which is the last line of the script. This is the snippet from the POD for the Simran::Log::Log module.

Error

Description

    If called in an array context, returns the complete history of err
+or messages thus far. Else, returns the latest error message if set.

      $errmsg = $session->error();

                    or

      foreach($session->error()){
         print “Error: $_\n”;
      }
[download]

The code for the above subroutine in the Log module is:

sub error {
  my $self = shift;
  return $error->msg();
}
[download]

where $error is the variable for a Simran::Error::Error object. Now the msg subroutine in the Error module is as follows:

sub msg {
  my $self = shift;

  if (wantarray) {
    return @{$self->{"HISTORY"}};
  }
  return $self->{"ERROR"};
}
[download]

Any suggestions as to why I’m banging my head into a wall would be welcomed. I will probably submit a patch to the author of these modules or outright ask if I can take them over (the last update was 26 April 2000, which is also the release date for both of them.)
TStanley
--------
It is God's job to forgive Osama Bin Laden. It is our job to arrange the meeting -- General Norman Schwartzkopf

Comment on Retrieving Error Messages Select or Download Code

Replies are listed 'Best First'.
Re: Retrieving Error Messages by pg (Canon) on Nov 18, 2002 at 18:52 UTC
The document says that, the error function, if it is used in a scalar context, which is the case you have now, it returns the latest error, if it is set. So it can return undef. Just do this: `print "Message is $msg\n" if $msg;` [download]	[reply] [d/l]
Re: Re: Retrieving Error Messages by pg (Canon) on Nov 18, 2002 at 18:54 UTC
Add one point, it should be a universal principle to check undef ALL the time, if you want robust code, not just for this Simran::Log::Log thing.	[reply]