10.4.1. Problem

10.4.2. Solution

$this_function = (caller(0))[3];

10.4.3. Discussion

The built-in function caller handles all of these. In scalar context it returns the calling function's package name, but in list context it returns much more. You can also pass it a number indicating how many frames (nested subroutine calls) back you'd like information about: 0 is your own function, 1 is your caller, and so on.

Here's the full syntax, where $i is how far back you're interested in:

($package, $filename, $line, $subr, $has_args, $wantarray 
#   0         1         2       3       4          5
 $evaltext, $is_require, $hints, $bitmask
#   6         7            8       9
)= caller($i);

Here's what each of those return values means:

$package

The package in which the code was compiled.

$filename

The name of the file in which the code was compiled, reporting -e if launched from that command-line switch, or - if the script was read from standard input.

$line

The line number from which that frame was called.

$subr

The name of that frame's function, including its package. Closures are indicated by names like main::_ _ANON_ _, which are not callable. In an eval, it contains (eval).

$has_args

Whether the function had its own @_ variable set up. It may be that there are no arguments, even if true. The only way for this to be false is if the function was called using the &fn notation instead of fn( ) or &fn( ).

$wantarray

The value the wantarray function would return for that stack frame; either true, false but defined, or else undefined. This tells whether the function was called in list, scalar, or void context (respectively).

$evaltext

The text of the current eval STRING, if any.

$is_require

Whether the code is currently being loaded by a do, require, or use.

$hints, $bitmask

These both contain pragmatic hints that the caller was compiled with. Consider them to be for internal use only by Perl itself.

$me  = whoami( );
$him = whowasi( );

sub whoami  { (caller(1))[3] }
sub whowasi { (caller(2))[3] }

These use arguments of 1 and 2 for parent and grandparent functions because the call to whoami or whowasi would itself be frame number 0.

10.4.4. See Also