Sub::Identify(3) User Contributed Perl Documentation Sub::Identify(3)

Sub::Identify - Retrieve names of code references

use Sub::Identify ':all';
my $subname = sub_name( $some_coderef );
my $packagename = stash_name( $some_coderef );
# or, to get all at once...
my $fully_qualified_name = sub_fullname( $some_coderef );
defined $subname
    and say "this coderef points to sub $subname in package $packagename";
my ($file, $line) = get_code_location( $some_coderef );
    and say "this coderef is defined at line $line in file $file";
is_sub_constant( $some_coderef )
    and say "this coderef points to a constant subroutine";

"Sub::Identify" allows you to retrieve the real name of code references.

It provides six functions, all of them taking a code reference.

"sub_name" returns the name of the code reference passed as an argument (or "__ANON__" if it's an anonymous code reference), "stash_name" returns its package, and "sub_fullname" returns the concatenation of the two.

"get_code_info" returns a list of two elements, the package and the subroutine name (in case of you want both and are worried by the speed.)

In case of subroutine aliasing, those functions always return the original name.

"get_code_location" returns a two-element list containing the file name and the line number where the subroutine has been defined.

"is_sub_constant" returns a boolean value indicating whether the subroutine is a constant or not.

By default "Sub::Identify" tries to load an XS implementation of the "get_code_info", "get_code_location" and (on perl versions 5.16.0 and later) "is_sub_constant" functions, for speed; if that fails, or if the environment variable "PERL_SUB_IDENTIFY_PP" is defined to a true value, it will fall back to a pure perl implementation, that uses perl's introspection mechanism, provided by the "B" module.

Sub::Util, part of the module distribution Scalar::List::Utils since version 1.40. Since this will be a core module starting with perl 5.22.0, it is encouraged to migrate to Sub::Util when possible.


A git repository for the sources is at

(c) Rafael Garcia-Suarez (rgs at consttype dot org) 2005, 2008, 2012, 2014, 2015

This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.

2023-07-25 perl v5.38.0