Returns the context of the current subroutine call. In scalar context,
returns the caller's package name if there is a caller, that is, if
we're in a subroutine or eval or require, and the undefined value
otherwise. In list context, returns
- # 0 1 2
- ($package, $filename, $line) = caller;
With EXPR, it returns some extra information that the debugger uses to print a stack trace. The value of EXPR indicates how many call frames to go back before the current one.
- # 0 1 2 3 4
- ($package, $filename, $line, $subroutine, $hasargs,
- # 5 6 7 8 9 10
- $wantarray, $evaltext, $is_require, $hints, $bitmask, $hinthash)
- = caller($i);
Here $subroutine may be (eval)
if the frame is not a subroutine
call, but an eval. In such a case additional elements $evaltext and
$is_require
are set: $is_require
is true if the frame is created by a
require or use statement, $evaltext contains the text of the
eval EXPR
statement. In particular, for an eval BLOCK
statement,
$subroutine is (eval)
, but $evaltext is undefined. (Note also that
each use statement creates a require frame inside an eval EXPR
frame.) $subroutine may also be (unknown)
if this particular
subroutine happens to have been deleted from the symbol table.
$hasargs
is true if a new instance of @_
was set up for the frame.
$hints
and $bitmask
contain pragmatic hints that the caller was
compiled with. The $hints
and $bitmask
values are subject to change
between versions of Perl, and are not meant for external use.
$hinthash
is a reference to a hash containing the value of %^H
when the
caller was compiled, or undef if %^H
was empty. Do not modify the values
of this hash, as they are the actual values stored in the optree.
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 the subroutine was invoked.
Be aware that the optimizer might have optimized call frames away before
caller had a chance to get the information. That means that caller(N)
might not return information about the call frame you expect it do, for
N > 1
. In particular, @DB::args
might have information from the
previous time caller was called.