Question

Here are the errors:

 $ perl ftper.pl Use of uninitialized value $id in hash element at /usr/lib/perl5/vendor_perl/5.1 /i686-cygwin/Tk/After.pm line 39. se of uninitialized value $id in hash element at /usr/lib/perl5/vendor_perl/5.1 /i686-cygwin/Tk/After.pm line 39. se of uninitialized value $id in hash element at /usr/lib/perl5/vendor_perl/5.1 /i686-cygwin/Tk/After.pm line 39. se of uninitialized value $id in hash element at /usr/lib/perl5/vendor_perl/5.1 /i686-cygwin/Tk/After.pm line 39. se of uninitialized value $id in hash element at /usr/lib/perl5/vendor_perl/5.1 /i686-cygwin/Tk/After.pm line 39. se of uninitialized value $id in hash element at /usr/lib/perl5/vendor_perl/5.1 /i686-cygwin/Tk/After.pm line 39. se of uninitialized value $id in delete at /usr/lib/perl5/vendor_perl/5.10/i686 cygwin/Tk/After.pm line 87. se of uninitialized value $id in delete at /usr/lib/perl5/vendor_perl/5.10/i686 cygwin/Tk/After.pm line 87. se of uninitialized value $id in delete at /usr/lib/perl5/vendor_perl/5.10/i686 cygwin/Tk/After.pm line 87. se of uninitialized value $id in delete at /usr/lib/perl5/vendor_perl/5.10/i686 cygwin/Tk/After.pm line 87. se of uninitialized value $id in delete at /usr/lib/perl5/vendor_perl/5.10/i686 cygwin/Tk/After.pm line 87. se of uninitialized value $id in delete at /usr/lib/perl5/vendor_perl/5.10/i686 cygwin/Tk/After.pm line 87.   

Here is the Perl/Tk code:

#! /usr/bin/perl -w  use strict; use Tk; use Tk::Scale; use File::DosGlob 'glob';   ##################################################################### # Define variables                              # ##################################################################### my $UserID; my $Password; my $BnsNode; my $Status_msg = 'BUILD SCRIPT!';  ##################################################################### # Window variables                          # ##################################################################### my $mw; my $frmUserID; my $lblUserID; my $frmPassword; my $lblPassword; my $edtUserID; my $edtPassword; my $frmTop; my $frmBig; my $frmButtonLine; my $btnExit; my $btnSubmit; my $lblStatus; my $lblUnixNode; my $frmUnixNode; my $edtUnixNode;  ################################################################# # Main Logic                            # ################################################################# init_mainwindow(); MainLoop;    ################################################################# # init_mainwindow                       # ################################################################# sub init_mainwindow {     $mw = MainWindow->new;     $mw->title('BUILD');     $mw->resizable(100, 100);     $mw->geometry('+175+100');      # Top Level frame for top section of form.     $frmTop = $mw->Frame(-bd => 2, -relief => 'ridge')         ->pack(-side => 'top', -fill => 'x', -pady => 3);       $frmUserID = $frmTop->Frame(-bd => 2)->pack(         -side => 'top', -fill => 'x');     $lblUserID = $frmUserID->Label(-text => 'Unix User ID:')         ->pack(-side => 'left');     $edtUserID = $frmUserID->Entry(-textvariable => \$UserID,         -background => 'white')->pack(-side => 'left');       $frmUnixNode = $frmTop->Frame(-bd => 2)->pack(     -side => 'top', -fill => 'x');     $lblUnixNode = $frmUserID->Label(-text => 'BNS Number')         ->pack(-side => 'left');     $edtUnixNode = $frmUserID->Entry(-textvariable => \$BnsNode,     -background => 'white')->pack(-side => 'left');   $frmPassword = $frmTop->Frame(-bd => 2)->pack(     -side => 'top', -fill => 'x'); $lblPassword = $frmPassword->Label(     -text => 'Password:    ')->pack(-side => 'left'); $edtPassword = $frmPassword->Entry(-textvariable => \$Password,     -background => 'white', -show => '*')     ->pack(-side => 'left');    # Top Level frame for bottom section of form. $frmButtonLine = $mw->Frame(-bd => 2, -relief => 'ridge')     ->pack(-side => 'top', -fill => 'x', -pady => 3);     $btnExit = $frmButtonLine->Button(-text => 'Exit',          -command => \&close_mw, -width => 6)->pack(         -side => 'right', -padx => 1);         $btnSubmit = $frmButtonLine->Button(-text => 'Run Script',      -command => \&execute_script, -width => 6)->pack(         -side => 'right', -padx => 1);     $lblStatus = $mw->Label(-textvariable => \$Status_msg,         -borderwidth => 2, -relief => 'groove')         ->pack(-fill => 'x', -side => 'bottom');      $edtUserID->focus;  }   ##################################################################### # excute_script                             # ##################################################################### sub execute_script {     unless (defined($UserID)) {         update_status('Must enter a user id!');         $edtUserID->focus;         return 0;     }     unless (defined($Password)) {         update_status('Must enter a password!');         $edtPassword->focus;         return 0;     }      update_status('$BnsNode ,$UserID '); }  ##################################################################### # close_mw                              # ##################################################################### sub close_mw {     $mw->destroy; }   ##################################################################### # update_status                             # ##################################################################### sub update_status {     my ($msg) = @_;      $Status_msg = $msg;     $lblStatus -> update; } 

Answer 1

The error messages themselves are straightforward enough:

Use of uninitialized value $id in hash element at …Tk/After.pm line 39.

Use of uninitialized value $id in delete at …Tk/After.pm line 87.

• "Use of uninitialized value" means that you used a value with a value of undef (undefined).
• $id is the name of the uninitialized variable.
• "in hash element" means that you used the value as hash key, e.g. $h{$id}
• "in delete" means that you used the value as a hash key to be deleted. e.g. delete $h{$id}
• "…Tx/After.pm" is the module where the error occurred.
• "line 39" and "line 87" are the line numbers (in the module) where the error occurred.

Tk::After provides callback scheduling to Perl/Tk applications. Things like "run this function after (or every) 500 ms." $id is the identifier for a specific callback on a widget.

What do do about the warnings is harder. I don’t see any explicit calls to Tk::After in the code you provided. It’s possible that there’s a bug in your Tk installation that’s triggering the warning. I don’t get any warnings when running it under Perl 5.10 with Tk 804.028.