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Perl Language Reference Manual
by Larry Wall and others
Paperback (6"x9"), 724 pages
ISBN 9781906966027
RRP £29.95 ($39.95)

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$PERLDB

$^P

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

0x01
Debug subroutine enter/exit.
0x02
Line-by-line debugging. Causes DB::DB() subroutine to be called for each statement executed. Also causes saving source code lines (like 0x400).
0x04
Switch off optimizations.
0x08
Preserve more data for future interactive inspections.
0x10
Keep info about source lines on which a subroutine is defined.
0x20
Start with single-step on.
0x40
Use subroutine address instead of name when reporting.
0x80
Report goto &subroutine as well.
0x100
Provide informative "file" names for evals based on the place they were compiled.
0x200
Provide informative names to anonymous subroutines based on the place they were compiled.
0x400
Save source code lines into @{"_<$filename"}.

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 "Guts of Perl debugging" (perldebguts) in the Perl C API and Internals Manual.

ISBN 9781906966027Perl Language Reference ManualSee the print edition