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
- $wantarray, $evaltext, $is_require, $hints, $bitmask) = caller($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.
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.