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

Hi,

I need to know which subroutine is running in order to display error message.

How do I get hold on subroutin name in a variable when the subroutine is running?

I prefare ??? to contain the running subroutine name. 

print "$CFG{ERROR_NOFILE} [ ??? ]\n";

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Re: how to get a subroutine name?
by LanX (Saint) on Jun 26, 2013 at 11:00 UTC
    see caller

      DB<111> sub tst { print ( (caller(0))[3] ) }

  DB<112> tst()
main::tst

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    Cheers Rolf

    ( addicted to the Perl Programming Language)

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Re: how to get a subroutine name?
by hdb (Monsignor) on Jun 26, 2013 at 11:10 UTC

    For historic reasons, I would propose to define a sub called __FUNC__ that returns the name of the subroutine in which it was called, see the following example: 

    use strict;
use warnings;

sub __FUNC__ { (caller 1)[3] }

sub func {
    print "We are now in ", __FUNC__, "\n";
}
 
func();

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    UPDATE: Removed a duplicated "print".

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      > For historic reasons,

      Sorry, which historic reasons?

      If you don't like caller's interface - where I sympathize - I'd rather propose something more flexible like returning a hashref:

         DB<116> sub __CALLER__ { 
           my $level = shift;
           my %hash; 
           @hash{qw/package filename line subroutine hasargs wantarray
+ evaltext is_require hints bitmask hinthash/} = caller($level+1); 
           return \%hash 
           }
  DB<130> sub tst { print __CALLER__->{subroutine} }

  DB<131> tst()
main::tst

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      or 
        DB<136> use Data::Dump qw/dd/

  DB<137> sub tst { dd __CALLER__ }

  DB<138> tst()
{
  bitmask     => "\0\0\0\0\0\0\0\0\0\0\0\0",
  evaltext    => undef,
  filename    => "(eval 108)[multi_perl5db.pl:644]",
  hasargs     => 1,
  hinthash    => undef,
  hints       => 256,
  is_require  => undef,
  line        => 2,
  "package"   => "main",
  subroutine  => "main::tst",
  "wantarray" => 1,
}

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      Though not sure about using this underscore __NAMESPACE__...

      And I'm pretty sure about reinventing the wheel ...

      ... CPAN is so big and I'm so lazy ;-)

      Cheers Rolf

      ( addicted to the Perl Programming Language)

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        I had to think about __LINE__ and __FILE__ etc from the good old times...

        Correction: I was thinking about good old __LINE__ and __FILE__...

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      5.16 added __SUB__ for this purpose.

      My bad! It returns a coderef.
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        However, __SUB__ returns a reference to the currently running subroutine according to perlsub. Not sure how you will get its name?

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