Contained in the file specified by the first filename on the command line.
(Note that systems supporting the C<#!> notation invoke interpreters this
-way. See L<Location of Perl>.)
+way. See L</Location of Perl>.)
=item 3.
=item B<-D>I<number>
-sets debugging flags. To watch how it executes your program, use
-B<-Dtls>. (This works only if debugging is compiled into your
-Perl.) Another nice value is B<-Dx>, which lists your compiled
-syntax tree. And B<-Dr> displays compiled regular expressions;
-the format of the output is explained in L<perldebguts>.
+sets debugging flags. This switch is enabled only if your perl binary has
+been built with debugging enabled: normal production perls won't have
+been.
+
+For example, to watch how perl executes your program, use B<-Dtls>.
+Another nice value is B<-Dx>, which lists your compiled syntax tree, and
+B<-Dr> displays compiled regular expressions; the format of the output is
+explained in L<perldebguts>.
As an alternative, specify a number instead of list of letters (e.g.,
B<-D14> is equivalent to B<-Dtls>):
- 1 p Tokenizing and parsing (with v, displays parse stack)
- 2 s Stack snapshots (with v, displays all stacks)
- 4 l Context (loop) stack processing
- 8 t Trace execution
- 16 o Method and overloading resolution
- 32 c String/numeric conversions
- 64 P Print profiling info, source file input state
- 128 m Memory and SV allocation
- 256 f Format processing
- 512 r Regular expression parsing and execution
- 1024 x Syntax tree dump
- 2048 u Tainting checks
- 4096 U Unofficial, User hacking (reserved for private,
- unreleased use)
- 8192 H Hash dump -- usurps values()
- 16384 X Scratchpad allocation
- 32768 D Cleaning up
- 65536 S Op slab allocation
- 131072 T Tokenizing
- 262144 R Include reference counts of dumped variables (eg when
- using -Ds)
- 524288 J show s,t,P-debug (don't Jump over) on opcodes within
- package DB
- 1048576 v Verbose: use in conjunction with other flags
- 2097152 C Copy On Write
- 4194304 A Consistency checks on internal structures
- 8388608 q quiet - currently only suppresses the "EXECUTING"
- message
- 16777216 M trace smart match resolution
- 33554432 B dump suBroutine definitions, including special Blocks
- like BEGIN
- 67108864 L trace Locale-related info; what gets output is very
- subject to change
+ 1 p Tokenizing and parsing (with v, displays parse
+ stack)
+ 2 s Stack snapshots (with v, displays all stacks)
+ 4 l Context (loop) stack processing
+ 8 t Trace execution
+ 16 o Method and overloading resolution
+ 32 c String/numeric conversions
+ 64 P Print profiling info, source file input state
+ 128 m Memory and SV allocation
+ 256 f Format processing
+ 512 r Regular expression parsing and execution
+ 1024 x Syntax tree dump
+ 2048 u Tainting checks
+ 4096 U Unofficial, User hacking (reserved for private,
+ unreleased use)
+ 8192 H Hash dump -- usurps values()
+ 16384 X Scratchpad allocation
+ 32768 D Cleaning up
+ 65536 S Op slab allocation
+ 131072 T Tokenizing
+ 262144 R Include reference counts of dumped variables
+ (eg when using -Ds)
+ 524288 J show s,t,P-debug (don't Jump over) on opcodes within
+ package DB
+ 1048576 v Verbose: use in conjunction with other flags
+ 2097152 C Copy On Write
+ 4194304 A Consistency checks on internal structures
+ 8388608 q quiet - currently only suppresses the "EXECUTING"
+ message
+ 16777216 M trace smart match resolution
+ 33554432 B dump suBroutine definitions, including special
+ Blocks like BEGIN
+ 67108864 L trace Locale-related info; what gets output is very
+ subject to change
+ 134217728 i trace PerlIO layer processing. Set PERLIO_DEBUG to
+ the filename to trace to.
All these flags require B<-DDEBUGGING> when you compile the Perl
executable (but see C<:opd> in L<Devel::Peek> or L<re/'debug' mode>
which may change this).
See the F<INSTALL> file in the Perl source distribution
-for how to do this. This flag is automatically set if you include B<-g>
-option when C<Configure> asks you about optimizer/debugger flags.
+for how to do this.
If you're just trying to get a print out of each line of Perl code
as it executes, the way that C<sh -x> provides for shell scripts,
=item PERLIO_DEBUG
X<PERLIO_DEBUG>
-If set to the name of a file or device, certain operations of PerlIO
-subsystem will be logged to that file, which is opened in append mode.
-Typical uses are in Unix:
+If set to the name of a file or device when Perl is run with the
+B<-Di> command-line switch, the logging of certain operations of
+the PerlIO subsystem will be redirected to the specified file rather
+than going to stderr, which is the default. The file is opened in append
+mode. Typical uses are in Unix:
- % env PERLIO_DEBUG=/dev/tty perl script ...
+ % env PERLIO_DEBUG=/tmp/perlio.log perl -Di script ...
and under Win32, the approximately equivalent:
> set PERLIO_DEBUG=CON
- perl script ...
+ perl -Di script ...
-This functionality is disabled for setuid scripts and for scripts run
-with B<-T>.
+This functionality is disabled for setuid scripts, for scripts run
+with B<-T>, and for scripts run on a Perl built without C<-DDEBUGGING>
+support.
=item PERLLIB
X<PERLLIB>
https://perl5.git.perl.org / perl5.git / blobdiff