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Given a subroutine reference, is there a way to find out the file and line number where the subroutine was declared? warn and friends seems to get this right, but I need this externally. Here's my test program:
#!/usr/bin/perl -l
use strict;
use warnings;
use B;
# line 99 'bin/some_code.pl'
{
no strict 'refs';
print B::svref_2object(\*{'Foo::some_sub'})->LINE;
print B::svref_2object(\&Foo::some_sub)->GV->LINE;
}
Foo::some_sub();
package Foo;
# line 23 'bin/some_file.pl'
sub some_sub {
warn "Got to here";
}
That outputs:
102
102
Got to here at 'bin/some_file.pl' line 24.
The line information is not what I'm expecting, so I assume I'm doing something wrong (B::GV has a corresponding FILE method, but until I get LINE working, it's not much use to me).
Is there some other way to get this information and am I doing something wrong in the above code?
Update: As it turns out, the 'FILE' and 'LINE' methods seem to work OK if I'm not using line directives. Looks like it may be a bug in the B::GV module.
237
One can avoid using the return statement. Defining Subroutines: The general form of defining the subroutine in Perl is as follows- sub subroutine_name { # body of method or subroutine } Calling Subroutines: In Perl subroutines can be called by passing the arguments list to it as follows-
You can pass various arguments to a subroutine like you do in any other programming language and they can be acessed inside the function using the special array @_. Thus the first argument to the function is in $_[0], the second is in $_[1], and so on.
To declare a subroutine, use one of these forms: sub NAME ; # A "forward" declaration. sub NAME ( PROTO ); # Ditto, but with prototype.
To insert a line after one already in the file, use the -n switch. It's just like -p except that it doesn't print $_ at the end of the loop, so you have to do that yourself. In this case, print $_ first, then print the line that you want to add. To delete lines, only print the ones that you want.
You could try looking at caller. This is what the debugger uses to build stack traces, so maybe it is what you want.
I don't think __LINE__, __FILE__ and __PACKAGE__ help you here as they only provide the location of the current point of execution, meaning that given a code reference or sub as in your code you will get the same results.
61
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