caller - get context of the current subroutine call
Returns the context of the current subroutine call. In a scalar context,
returns TRUE if there is a caller, that is, if we're in a subroutine or
, and FALSE otherwise. In a list context, returns
($package, $filename, $line) = caller;
With EXPR, it returns some extra information that the debugger uses to
print a stack trace. The value of EXPR indicates how many call frames
to go back before the current one.
($package, $filename, $line,
$subroutine, $hasargs, $wantargs) = caller($i);
Furthermore, when called from within the DB package, caller returns more
detailed information: it sets the list variable @DB::args to be the
arguments with which that subroutine was invoked.