Perl 5 version 8.9 documentation
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
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_requireis true if the frame is created by a
usestatement, $evaltext contains the text of the
eval EXPRstatement. In particular, for an
eval BLOCKstatement, $subroutine is
(eval), but $evaltext is undefined. (Note also that each
usestatement creates a
requireframe inside an
eval EXPRframe.) $subroutine may also be
(unknown)if this particular subroutine happens to have been deleted from the symbol table.
$hasargsis true if a new instance of
@_was set up for the frame.
$bitmaskcontain pragmatic hints that the caller was compiled with. The
$bitmaskvalues 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::argsto be the arguments with which the subroutine was invoked.
Be aware that the optimizer might have optimized call frames away before
callerhad 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::argsmight have information from the previous time