$^P

$^P

The internal variable for debugging support. The meanings of the various bits are subject to change, but currently indicate:

0

x01

Debug subroutine enter/exit.

0

x02

Line-by-line debugging. Causes DB::DB() subroutine to be called for each statement executed. Also causes saving source code lines (like 0x400).

0

x04

Switch off optimizations.

0

x08

Preserve more data for future interactive inspections.

0

x10

Keep info about source lines on which a subroutine is defined.

0

x20

Start with single-step on.

0

x40

Use subroutine address instead of name when reporting.

0

x80

Report goto &subroutine as well.

0

x100

Provide informative "file" names for evals based on the place they were compiled.

0

x200

Provide informative names to anonymous subroutines based on the place they were compiled.

0

x400

Save source code lines into @{"_<$filename"} .

0

x800

When saving source, include evals that generate no subroutines.

0

x1000

When saving source, include source that did not compile.

Some bits may be relevant at compile-time only, some at run-time only. This is a new mechanism and the details may change. See also perldebguts.