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 oreval orrequire, and the undefined value otherwise. In 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, $hasargs,$wantarray, $evaltext, $is_require, $hints, $bitmask) = caller($i);Here $subroutine may be(eval) if the frame is not a subroutine call, but aneval. In such a case additional elements $evaltext and$is_require are set:$is_require is true if the frame is created by arequire oruse statement, $evaltext contains the text of theeval EXPR statement. In particular, for aneval BLOCK statement, $filename is(eval), but $evaltext is undefined. (Note also that eachuse statement creates arequire frame inside aneval 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 beforecaller had a chance to get the information. That means thatcaller(N) might not return information about the call frame you expect it do, forN > 1. In particular,@DB::args might have information from the previous timecaller was called.
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