How to determine current line executing in Script

[bearslumber]

Hallo Monks,

I am trying to find a way to dynamically determine the current line being executed in my script.

I have a batch script which I accumulate a progress report or log whilst it is running and then output the log to a file on completion. I wish to add the current line number being executed in the script to each instance in the report

The following describes a snippet of code to demonstrate my requirement. I have annotated the code with line numbers for demonstration purposes

1. #!/usr/bin/perl
2. use warnings;
3. use strict;
4. 
5. my @log ;
6.
.
.
.
25. my $success = &Get_Item_From_File ($file)
26. 
27. if ($Success) {
28.     $_ref_DB_DD_OSD = &Get_DB_OSD ($_ref_Model) 
29. }
30. else {
31.     push (@log, "Read $file not successfull" . "31") ;
32. }
.
.
.
1024 print <FILE> @log ;
1025 exit ;
.

The following demonstrates the hard coded method at line 31, but if there is a way of determining this dynamically then this would reduce the need to have to manually update the hard coded value whenever the script is modified.

I envisage substituting line 31 as follows:

 push (@log, "Read $file not successfull" . &function_returning_current_line) ;

or anything similar; i.e. Get a near enough line number before the call to push etc

Any help would be greatly appreciated

Best regards

Lucas Redding AKA Bearslumber

[Corion]

Also see perldata about __LINE__, and possibly caller, should you want to put your logging code into a subroutine.

[ccn]

use Log::Log4perl;

[bearslumber]

Hi ccn

Many thanks for your prompt reply. I blinked and you had already replied.

I have looked at Log4Perl and having read the POD, it does just the job. i.e. layout = %L.

Much appreciated.

Lucas AKA: Bearslumber

[clinton]

You can use __LINE__. See "Special literals" in perldata.

[bearslumber]

All.

Many thanks for your replies. I am grateful for all responses.

Here is my conclusion...

1. Log4Perl: Brilliant package. Does everything I could ever have imagined would be required in a log. I just wish I had known about it when I embarked on this project. I would use this if I was to start again.

2. Perdata __LINE__: Getting there. A quick solution, seems to be just what I was hoping for.

3. caller: This is icing on the cake.

4. Make use of warn, $SIG{__WARN__} and END {...}: And I can now ensure I get the log out regardless of the death of my script.

I am truly spoilt for choice, and for this project will definately be using caller and will Make use of warn, $SIG{__WARN__} and END {...}:.

I shall definitley find use for verything sometime in future.

Many thanks again.

Lucas Bearslumber

[Anonymous Monk]

Make use of warn, $SIG{__WARN__} and END {...}. If the argument to warn doesn't end with a new line ( warn $x." "; ) then the line number will be appended. In $SIG{__WARN__} do a "push(@log,"@_");". In the END block print @log. You probably should add a $SIG{__DIE__} where you also do the "push(@log ..." before you re-raise the die. That way you'll get a log if you "die".

[Anonymous Monk]

#!/usr/bin/perl

use strict;
use warnings;

my @log="\n";

BEGIN {
    $SIG{__WARN__}=sub {
            push(@log,"@_");
             };
    $SIG{__DIE__}=sub {
            push(@log,"@_");
             };
     } # BEGIN
END {
    if (@log) {
        print @log;
         };
     } # END

warn "a warning ";
my $warning="just another warning\n";
warn $warning." ";
die "death by request";