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_require are set:
$is_require is true if the frame is created by a
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.
$bitmask contain pragmatic hints that the caller was compiled with. The
$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.