releases of Perl are shepherded by a ``pumpking'', a porter
responsible for gathering patches, deciding on a patch-by-patch
feature-by-feature basis what will and will not go into the release.
-For instance, Gurusamy Sarathy is the pumpking for the 5.6 release of
-Perl.
+For instance, Gurusamy Sarathy was the pumpking for the 5.6 release of
+Perl, and Jarkko Hietaniemi is the pumpking for the 5.8 release, and
+Hugo van der Sanden will be the pumpking for the 5.10 release.
In addition, various people are pumpkings for different things. For
instance, Andy Dougherty and Jarkko Hietaniemi share the I<Configure>
-pumpkin, and Tom Christiansen is the documentation pumpking.
+pumpkin.
Larry sees Perl development along the lines of the US government:
there's the Legislature (the porters), the Executive branch (the
unlikely that nonportable additions to the Perl language will be
accepted.
+=item Is the implementation tested?
+
+Patches which change behaviour (fixing bugs or introducing new features)
+must include regression tests to verify that everything works as expected.
+Without tests provided by the original author, how can anyone else changing
+perl in the future be sure that they haven't unwittingly broken the behaviour
+the patch implements? And without tests, how can the patch's author be
+confident that his/her hard work put into the patch won't be accidentally
+thrown away by someone in the future?
+
=item Is there enough documentation?
Patches without documentation are probably ill-thought out or
incomplete. Nothing can be added without documentation, so submitting
a patch for the appropriate manpages as well as the source code is
-always a good idea. If appropriate, patches should add to the test
-suite as well.
+always a good idea.
=item Is there another way to do it?
=head2 Keeping in sync
The source code to the Perl interpreter, in its different versions, is
-kept in a repository managed by a revision control system (which is
-currently the Perforce program, see http://perforce.com/). The
+kept in a repository managed by a revision control system ( which is
+currently the Perforce program, see http://perforce.com/ ). The
pumpkings and a few others have access to the repository to check in
changes. Periodically the pumpking for the development version of Perl
will release a new version, so the rest of the porters can see what's
that describe the individual changes that have happened since the last
public release are available at this location:
+ http://public.activestate.com/gsar/APC/
ftp://ftp.linux.activestate.com/pub/staff/gsar/APC/
+If you're looking for a particular change, or a change that affected
+a particular set of files, you may find the B<Perl Repository Browser>
+useful:
+
+ http://public.activestate.com/cgi-bin/perlbrowse
+
+You may also want to subscribe to the perl5-changes mailing list to
+receive a copy of each patch that gets submitted to the maintenance
+and development "branches" of the perl repository. See
+http://lists.perl.org/ for subscription information.
+
If you are a member of the perl5-porters mailing list, it is a good
thing to keep in touch with the most recent changes. If not only to
verify if what you would have posted as a bug report isn't already
available to the LAN and sync the other machines against this
directory.
-From http://rsync.samba.org/README.html:
+From http://rsync.samba.org/README.html :
"Rsync uses rsh or ssh for communication. It does not need to be
setuid and requires no special privileges for installation. It
It's then up to you to apply these patches, using something like
- # last=`ls -rt1 *.gz | tail -1`
+ # last=`ls -t *.gz | sed q`
# rsync -avz rsync://ftp.linux.activestate.com/perl-current-diffs/ .
# find . -name '*.gz' -newer $last -exec gzcat {} \; >blead.patch
# cd ../perl-current
Since you don't have to apply the patches yourself, you are sure all
files in the source tree are in the right state.
-=item It's more recent
-
-According to Gurusamy Sarathy:
-
- "... The rsync mirror is automatic and syncs with the repository
- every five minutes.
-
- "Updating the patch area still requires manual intervention
- (with all the goofiness that implies, which you've noted) and
- is typically on a daily cycle. Making this process automatic
- is on my tuit list, but don't ask me when."
-
=item It's more reliable
-Well, since the patches are updated by hand, I don't have to say any
-more ... (see Sarathy's remark).
+While both the rsync-able source and patch areas are automatically
+updated every few minutes, keep in mind that applying patches may
+sometimes mean careful hand-holding, especially if your version of
+the C<patch> program does not understand how to deal with new files,
+files with 8-bit characters, or files without trailing newlines.
=back
=back
+=head2 Working with the source
+
+Because you cannot use the Perforce client, you cannot easily generate
+diffs against the repository, nor will merges occur when you update
+via rsync. If you edit a file locally and then rsync against the
+latest source, changes made in the remote copy will I<overwrite> your
+local versions!
+
+The best way to deal with this is to maintain a tree of symlinks to
+the rsync'd source. Then, when you want to edit a file, you remove
+the symlink, copy the real file into the other tree, and edit it. You
+can then diff your edited file against the original to generate a
+patch, and you can safely update the original tree.
+
+Perl's F<Configure> script can generate this tree of symlinks for you.
+The following example assumes that you have used rsync to pull a copy
+of the Perl source into the F<perl-rsync> directory. In the directory
+above that one, you can execute the following commands:
+
+ mkdir perl-dev
+ cd perl-dev
+ ../perl-rsync/Configure -Dmksymlinks -Dusedevel -D"optimize=-g"
+
+This will start the Perl configuration process. After a few prompts,
+you should see something like this:
+
+ Symbolic links are supported.
+
+ Checking how to test for symbolic links...
+ Your builtin 'test -h' may be broken.
+ Trying external '/usr/bin/test -h'.
+ You can test for symbolic links with '/usr/bin/test -h'.
+
+ Creating the symbolic links...
+ (First creating the subdirectories...)
+ (Then creating the symlinks...)
+
+The specifics may vary based on your operating system, of course.
+After you see this, you can abort the F<Configure> script, and you
+will see that the directory you are in has a tree of symlinks to the
+F<perl-rsync> directories and files.
+
+If you plan to do a lot of work with the Perl source, here are some
+Bourne shell script functions that can make your life easier:
+
+ function edit {
+ if [ -L $1 ]; then
+ mv $1 $1.orig
+ cp $1.orig $1
+ vi $1
+ else
+ /bin/vi $1
+ fi
+ }
-=head2 Perlbug remote interface
-
-=over 4
-
-There are three (3) remote administrative interfaces for modifying bug status, category, etc. In all cases an admin must be first registered with the Perlbug database by sending an email request to richard@perl.org or bugmongers@perl.org.
-
-The main requirement is the willingness to classify, (with the emphasis on closing where possible :), outstanding bugs. Further explanation can be garnered from the web at http://bugs.perl.org/, or by asking on the admin mailing list at: bugmongers@perl.org
-
-For more info on the web see
-
- http://bugs.perl.org/perlbug.cgi?req=spec
-
-
-B<The interfaces:>
-
-
-=item 1 http://bugs.perl.org
-
-Login via the web, (remove B<admin/> if only browsing), where interested Cc's, tests, patches and change-ids, etc. may be assigned.
-
- http://bugs.perl.org/admin/index.html
-
-
-=item 2 bugdb@perl.org
-
-Where the subject line is used for commands:
-
- To: bugdb@perl.org
- Subject: -a close bugid1 bugid2 aix install
-
- To: bugdb@perl.org
- Subject: -h
+ function unedit {
+ if [ -L $1.orig ]; then
+ rm $1
+ mv $1.orig $1
+ fi
+ }
+Replace "vi" with your favorite flavor of editor.
+
+Here is another function which will quickly generate a patch for the
+files which have been edited in your symlink tree:
+
+ mkpatchorig() {
+ local diffopts
+ for f in `find . -name '*.orig' | sed s,^\./,,`
+ do
+ case `echo $f | sed 's,.orig$,,;s,.*\.,,'` in
+ c) diffopts=-p ;;
+ pod) diffopts='-F^=' ;;
+ *) diffopts= ;;
+ esac
+ diff -du $diffopts $f `echo $f | sed 's,.orig$,,'`
+ done
+ }
-=item 3 commands_and_bugdids@bugs.perl.org
+This function produces patches which include enough context to make
+your changes obvious. This makes it easier for the Perl pumpking(s)
+to review them when you send them to the perl5-porters list, and that
+means they're more likely to get applied.
-Where the address itself is the source for the commands:
+This function assumed a GNU diff, and may require some tweaking for
+other diff variants.
- To: close_bugid1_bugid2_aix@bugs.perl.org
+=head2 Perlbug administration
- To: help@bugs.perl.org
+There is a single remote administrative interface for modifying bug status,
+category, open issues etc. using the B<RT> I<bugtracker> system, maintained
+by I<Robert Spier>. Become an administrator, and close any bugs you can get
+your sticky mitts on:
+ http://rt.perl.org
-=item notes, patches, tests
+The bugtracker mechanism for B<perl5> bugs in particular is at:
-For patches and tests, the message body is assigned to the appropriate bug/s and forwarded to p5p for their attention.
+ http://bugs6.perl.org/perlbug
- To: test_<bugid1>_aix_close@bugs.perl.org
- Subject: this is a test for the (now closed) aix bug
+To email the bug system administrators:
- Test is the body of the mail
+ "perlbug-admin" <perlbug-admin@perl.org>
-=back
=head2 Submitting patches
copy (see L<Patching a core module>). This lets other porters review
your patch, which catches a surprising number of errors in patches.
Either use the diff program (available in source code form from
-I<ftp://ftp.gnu.org/pub/gnu/>), or use Johan Vromans' I<makepatch>
+ftp://ftp.gnu.org/pub/gnu/ , or use Johan Vromans' I<makepatch>
(available from I<CPAN/authors/id/JV/>). Unified diffs are preferred,
but context diffs are accepted. Do not send RCS-style diffs or diffs
without context lines. More information is given in the
Perl (if you can't get Perl to work, send mail to the address
I<perlbug@perl.org> or I<perlbug@perl.com>). Reporting bugs through
I<perlbug> feeds into the automated bug-tracking system, access to
-which is provided through the web at I<http://bugs.perl.org/>. It
+which is provided through the web at http://bugs.perl.org/ . It
often pays to check the archives of the perl5-porters mailing list to
see whether the bug you're reporting has been reported before, and if
so whether it was considered a bug. See above for the location of
the searchable archives.
-The CPAN testers (I<http://testers.cpan.org/>) are a group of
-volunteers who test CPAN modules on a variety of platforms. Perl Labs
-(I<http://labs.perl.org/>) automatically tests Perl source releases on
-platforms and gives feedback to the CPAN testers mailing list. Both
-efforts welcome volunteers.
+The CPAN testers ( http://testers.cpan.org/ ) are a group of
+volunteers who test CPAN modules on a variety of platforms. Perl
+Smokers ( http://archives.develooper.com/daily-build@perl.org/ )
+automatically tests Perl source releases on platforms with various
+configurations. Both efforts welcome volunteers.
It's a good idea to read and lurk for a while before chipping in.
That way you'll get to see the dynamic of the conversations, learn the
You might also want to look at Gisle Aas's illustrated perlguts -
there's no guarantee that this will be absolutely up-to-date with the
latest documentation in the Perl core, but the fundamentals will be
-right. (http://gisle.aas.no/perl/illguts/)
+right. ( http://gisle.aas.no/perl/illguts/ )
=item L<perlxstut> and L<perlxs>
=item The perl5-porters FAQ
-This is posted to perl5-porters at the beginning on every month, and
-should be available from http://perlhacker.org/p5p-faq; alternatively,
-you can get the FAQ emailed to you by sending mail to
-C<perl5-porters-faq@perl.org>. It contains hints on reading
-perl5-porters, information on how perl5-porters works and how Perl
-development in general works.
+This should be available from http://simon-cozens.org/writings/p5p-faq ;
+alternatively, you can get the FAQ emailed to you by sending mail to
+C<perl5-porters-faq@perl.org>. It contains hints on reading perl5-porters,
+information on how perl5-porters works and how Perl development in general
+works.
=back
Line 13 manipulates the flags; since we've changed the PV, any IV or NV
values will no longer be valid: if we have C<$a=10; $a.="6";> we don't
-want to use the old IV of 10. C<SvPOK_only_utf8> is a special UTF8-aware
+want to use the old IV of 10. C<SvPOK_only_utf8> is a special UTF-8-aware
version of C<SvPOK_only>, a macro which turns off the IOK and NOK flags
and turns on POK. The final C<SvTAINT> is a macro which launders tainted
data if taint mode is turned on.
The easiest way to examine the op tree is to stop Perl after it has
finished parsing, and get it to dump out the tree. This is exactly what
-the compiler backends L<B::Terse|B::Terse> and L<B::Debug|B::Debug> do.
+the compiler backends L<B::Terse|B::Terse>, L<B::Concise|B::Concise>
+and L<B::Debug|B::Debug> do.
Let's have a look at how Perl sees C<$a = $b + $c>:
to L<perlguts/Background and PERL_IMPLICIT_CONTEXT> for information on
the C<[pad]THX_?> macros.
+=head2 The .i Targets
+
+You can expand the macros in a F<foo.c> file by saying
+
+ make foo.i
+
+which will expand the macros using cpp. Don't be scared by the results.
=head2 Poking at Perl
=item print
Execute the given C code and print its results. B<WARNING>: Perl makes
-heavy use of macros, and F<gdb> is not aware of macros. You'll have to
-substitute them yourself. So, for instance, you can't say
+heavy use of macros, and F<gdb> does not necessarily support macros
+(see later L</"gdb macro support">). You'll have to substitute them
+yourself, or to invoke cpp on the source code files
+(see L</"The .i Targets">)
+So, for instance, you can't say
print SvPV_nolen(sv)
print Perl_sv_2pv_nolen(sv)
+=back
+
You may find it helpful to have a "macro dictionary", which you can
produce by saying C<cpp -dM perl.c | sort>. Even then, F<cpp> won't
-recursively apply the macros for you.
+recursively apply those macros for you.
-=back
+=head2 gdb macro support
+
+Recent versions of F<gdb> have fairly good macro support, but
+in order to use it you'll need to compile perl with macro definitions
+included in the debugging information. Using F<gcc> version 3.1, this
+means configuring with C<-Doptimize=-g3>. Other compilers might use a
+different switch (if they support debugging macros at all).
=head2 Dumping Perl Data Structures
on and create a simple patch. Here's something Larry suggested: if a
C<U> is the first active format during a C<pack>, (for example,
C<pack "U3C8", @stuff>) then the resulting string should be treated as
-UTF8 encoded.
+UTF-8 encoded.
How do we prepare to fix this up? First we locate the code in question -
the C<pack> happens at runtime, so it's going to be in one of the F<pp>
while (pat < patend) {
Now if we see a C<U> which was at the start of the string, we turn on
-the UTF8 flag for the output SV, C<cat>:
+the C<UTF8> flag for the output SV, C<cat>:
+ if (datumtype == 'U' && pat==patcopy+1)
+ SvUTF8_on(cat);
Unicode strings.
t/op/pack.t has a sensible ok() function, but if it didn't we could
-write one easily.
+use the one from t/test.pl.
- my $test = 1;
- sub ok {
- my($ok, $name) = @_;
-
- # You have to do it this way or VMS will get confused.
- print $ok ? "ok $test - $name\n" : "not ok $test - $name\n";
-
- printf "# Failed test at line %d\n", (caller)[2] unless $ok;
-
- $test++;
- return $ok;
- }
+ require './test.pl';
+ plan( tests => 159 );
so instead of this:
print 'not ' unless "1.20.300.4000" eq sprintf "%vd", pack("U*",1,20,300,4000);
print "ok $test\n"; $test++;
-we can write the (somewhat) more sensible:
+we can write the more sensible (see L<Test::More> for a full
+explanation of is() and other testing functions).
- ok( "1.20.300.4000" eq sprintf "%vd", pack("U*",1,20,300,4000),
+ is( "1.20.300.4000", sprintf "%vd", pack("U*",1,20,300,4000),
"U* produces unicode" );
Now we'll test that we got that space-at-the-beginning business right:
- ok( "1.20.300.4000" eq sprintf "%vd", pack(" U*",1,20,300,4000),
+ is( "1.20.300.4000", sprintf "%vd", pack(" U*",1,20,300,4000),
" with spaces at the beginning" );
And finally we'll test that we don't make Unicode strings if C<U> is B<not>
the first active format:
- ok( v1.20.300.4000 ne sprintf "%vd", pack("C0U*",1,20,300,4000),
+ isnt( v1.20.300.4000, sprintf "%vd", pack("C0U*",1,20,300,4000),
"U* not first isn't unicode" );
-Mustn't forget to change the number of tests which appears at the top, or
-else the automated tester will get confused:
+Mustn't forget to change the number of tests which appears at the top,
+or else the automated tester will get confused. This will either look
+like this:
+
+ print "1..156\n";
- -print "1..156\n";
- +print "1..159\n";
+or this:
+
+ plan( tests => 156 );
We now compile up Perl, and run it through the test suite. Our new
tests pass, hooray!
=item *
If the pattern begins with a C<U>, the resulting string will be treated
- as Unicode-encoded. You can force UTF8 encoding on in a string with an
- initial C<U0>, and the bytes that follow will be interpreted as Unicode
- characters. If you don't want this to happen, you can begin your pattern
- with C<C0> (or anything else) to force Perl not to UTF8 encode your
+ as UTF-8-encoded Unicode. You can force UTF-8 encoding on in a string
+ with an initial C<U0>, and the bytes that follow will be interpreted as
+ Unicode characters. If you don't want this to happen, you can begin your
+ pattern with C<C0> (or anything else) to force Perl not to UTF-8 encode your
string, and then follow this with a C<U*> somewhere in your pattern.
All done. Now let's create the patch. F<Porting/patching.pod> tells us
to explore all boundary conditions that your new function is expected
to handle. If your new function is used only by one module (e.g. toke),
then it should probably be named S_your_function (for static); on the
-other hand, if you expect it to accessable from other functions in
+other hand, if you expect it to accessible from other functions in
Perl, you should name it Perl_your_function. See L<perlguts/Internal Functions>
for more details.
this when you post your patch to P5P; the pumpking needs to know this.
When you write your new code, please be conscious of existing code
-conventions used in the perl source files. See <perlstyle> for
+conventions used in the perl source files. See L<perlstyle> for
details. Although most of the guidelines discussed seem to focus on
Perl code, rather than c, they all apply (except when they don't ;).
See also I<Porting/patching.pod> file in the Perl source distribution
Test on as many platforms as you can find. Test as many perl
Configure options as you can (e.g. MULTIPLICITY). If you have
profiling or memory tools, see L<EXTERNAL TOOLS FOR DEBUGGING PERL>
-below for how to use them to futher test your code. Remember that
+below for how to use them to further test your code. Remember that
most of the people on P5P are doing this on their own time and
don't have the time to debug your code.
=item F<t/cmd/>
These test the basic control structures, C<if/else>, C<while>,
-subroutines, etc...
+subroutines, etc.
=item F<t/comp/>
Testing features of how perl actually runs, including exit codes and
handling of PERL* environment variables.
+=item F<t/uni/>
+
+Tests for the core support of Unicode.
+
+=item F<t/win32/>
+
+Windows-specific tests.
+
+=item F<t/x2p>
+
+A test suite for the s2p converter.
+
=back
The core uses the same testing style as the rest of Perl, a simple
"ok/not ok" run through Test::Harness, but there are a few special
considerations.
-For most libraries and extensions, you'll want to use the Test::More
-library rather than rolling your own test functions. If a module test
-doesn't use Test::More, consider rewriting it so it does. For the
-rest it's best to use a simple C<print "ok $test_num\n"> style to avoid
-broken core functionality from causing the whole test to collapse.
+There are three ways to write a test in the core. Test::More,
+t/test.pl and ad hoc C<print $test ? "ok 42\n" : "not ok 42\n">. The
+decision of which to use depends on what part of the test suite you're
+working on. This is a measure to prevent a high-level failure (such
+as Config.pm breaking) from causing basic functionality tests to fail.
+
+=over 4
+
+=item t/base t/comp
+
+Since we don't know if require works, or even subroutines, use ad hoc
+tests for these two. Step carefully to avoid using the feature being
+tested.
+
+=item t/cmd t/run t/io t/op
+
+Now that basic require() and subroutines are tested, you can use the
+t/test.pl library which emulates the important features of Test::More
+while using a minimum of core features.
+
+You can also conditionally use certain libraries like Config, but be
+sure to skip the test gracefully if it's not there.
+
+=item t/lib ext lib
+
+Now that the core of Perl is tested, Test::More can be used. You can
+also use the full suite of core modules in the tests.
+
+=back
When you say "make test" Perl uses the F<t/TEST> program to run the
test suite. All tests are run from the F<t/> directory, B<not> the
boils down to using File::Spec and avoiding things like C<fork()> and
C<system()> unless absolutely necessary.
+=head2 Special Make Test Targets
+
+There are various special make targets that can be used to test Perl
+slightly differently than the standard "test" target. Not all them
+are expected to give a 100% success rate. Many of them have several
+aliases.
+
+=over 4
+
+=item coretest
+
+Run F<perl> on all core tests (F<t/*> and F<lib/[a-z]*> pragma tests).
+
+=item test.deparse
+
+Run all the tests through B::Deparse. Not all tests will succeed.
+
+=item test.taintwarn
+
+Run all tests with the B<-t> command-line switch. Not all tests
+are expected to succeed (until they're specifically fixed, of course).
+
+=item minitest
+
+Run F<miniperl> on F<t/base>, F<t/comp>, F<t/cmd>, F<t/run>, F<t/io>,
+F<t/op>, and F<t/uni> tests.
+
+=item test.valgrind check.valgrind utest.valgrind ucheck.valgrind
+
+(Only in Linux) Run all the tests using the memory leak + naughty
+memory access tool "valgrind". The log files will be named
+F<testname.valgrind>.
+
+=item test.third check.third utest.third ucheck.third
+
+(Only in Tru64) Run all the tests using the memory leak + naughty
+memory access tool "Third Degree". The log files will be named
+F<perl3.log.testname>.
+
+=item test.torture torturetest
+
+Run all the usual tests and some extra tests. As of Perl 5.8.0 the
+only extra tests are Abigail's JAPHs, F<t/japh/abigail.t>.
+
+You can also run the torture test with F<t/harness> by giving
+C<-torture> argument to F<t/harness>.
+
+=item utest ucheck test.utf8 check.utf8
+
+Run all the tests with -Mutf8. Not all tests will succeed.
+
+=item test_harness
+
+Run the test suite with the F<t/harness> controlling program, instead of
+F<t/TEST>. F<t/harness> is more sophisticated, and uses the
+L<Test::Harness> module, thus using this test target supposes that perl
+mostly works. The main advantage for our purposes is that it prints a
+detailed summary of failed tests at the end. Also, unlike F<t/TEST>, it
+doesn't redirect stderr to stdout.
+
+=back
+
+=head2 Running tests by hand
+
+You can run part of the test suite by hand by using one the following
+commands from the F<t/> directory :
+
+ ./perl -I../lib TEST list-of-.t-files
+
+or
+
+ ./perl -I../lib harness list-of-.t-files
+
+(if you don't specify test scripts, the whole test suite will be run.)
+
+You can run an individual test by a command similar to
+
+ ./perl -I../lib patho/to/foo.t
+
+except that the harnesses set up some environment variables that may
+affect the execution of the test :
+
+=over 4
+
+=item PERL_CORE=1
+
+indicates that we're running this test part of the perl core test suite.
+This is useful for modules that have a dual life on CPAN.
+
+=item PERL_DESTRUCT_LEVEL=2
+
+is set to 2 if it isn't set already (see L</PERL_DESTRUCT_LEVEL>)
+
+=item PERL
+
+(used only by F<t/TEST>) if set, overrides the path to the perl executable
+that should be used to run the tests (the default being F<./perl>).
+
+=item PERL_SKIP_TTY_TEST
+
+if set, tells to skip the tests that need a terminal. It's actually set
+automatically by the Makefile, but can also be forced artificially by
+running 'make test_notty'.
+
+=back
=head1 EXTERNAL TOOLS FOR DEBUGGING PERL
meant as a guide to interfacing these tools with Perl, not
as any kind of guide to the use of the tools themselves.
+B<NOTE 1>: Running under memory debuggers such as Purify, valgrind, or
+Third Degree greatly slows down the execution: seconds become minutes,
+minutes become hours. For example as of Perl 5.8.1, the
+ext/Encode/t/Unicode.t takes extraordinarily long to complete under
+e.g. Purify, Third Degree, and valgrind. Under valgrind it takes more
+than six hours, even on a snappy computer-- the said test must be
+doing something that is quite unfriendly for memory debuggers. If you
+don't feel like waiting, that you can simply kill away the perl
+process.
+
+B<NOTE 2>: To minimize the number of memory leak false alarms (see
+L</PERL_DESTRUCT_LEVEL> for more information), you have to have
+environment variable PERL_DESTRUCT_LEVEL set to 2. The F<TEST>
+and harness scripts do that automatically. But if you are running
+some of the tests manually-- for csh-like shells:
+
+ setenv PERL_DESTRUCT_LEVEL 2
+
+and for Bourne-type shells:
+
+ PERL_DESTRUCT_LEVEL=2
+ export PERL_DESTRUCT_LEVEL
+
+or in UNIXy environments you can also use the C<env> command:
+
+ env PERL_DESTRUCT_LEVEL=2 valgrind ./perl -Ilib ...
+
+B<NOTE 3>: There are known memory leaks when there are compile-time
+errors within eval or require, seeing C<S_doeval> in the call stack
+is a good sign of these. Fixing these leaks is non-trivial,
+unfortunately, but they must be fixed eventually.
+
=head2 Rational Software's Purify
Purify is a commercial tool that is helpful in identifying
optimal testing with Purify. Purify is available under
Windows NT, Solaris, HP-UX, SGI, and Siemens Unix.
-The only currently known leaks happen when there are
-compile-time errors within eval or require. (Fixing these
-is non-trivial, unfortunately, but they must be fixed
-eventually.)
-
=head2 Purify on Unix
On Unix, Purify creates a new Perl binary. To get the most
setenv PURIFYOPTIONS "-chain-length=25"
+In Bourne-type shells:
+
+ PURIFYOPTIONS="..."
+ export PURIFYOPTIONS
+
+or if you have the "env" utility:
+
+ env PURIFYOPTIONS="..." ../pureperl ...
+
=head2 Purify on NT
Purify on Windows NT instruments the Perl binary 'perl.exe'
which would instrument Perl in memory, run Perl on test.pl,
then finally report any memory problems.
-=head2 Compaq's/Digital's Third Degree
+=head2 valgrind
+
+The excellent valgrind tool can be used to find out both memory leaks
+and illegal memory accesses. As of August 2003 it unfortunately works
+only on x86 (ELF) Linux. The special "test.valgrind" target can be used
+to run the tests under valgrind. Found errors and memory leaks are
+logged in files named F<test.valgrind>.
+
+As system libraries (most notably glibc) are also triggering errors,
+valgrind allows to suppress such errors using suppression files. The
+default suppression file that comes with valgrind already catches a lot
+of them. Some additional suppressions are defined in F<t/perl.supp>.
+
+To get valgrind and for more information see
+
+ http://developer.kde.org/~sewardj/
+
+=head2 Compaq's/Digital's/HP's Third Degree
Third Degree is a tool for memory leak detection and memory access checks.
It is one of the many tools in the ATOM toolkit. The toolkit is only
documentation is available in the Compaq "Tru64 UNIX Programmer's
Guide", chapter "Debugging Programs with Third Degree".
-The "test.third" leaves a lot of files named F<perl.3log.*> in the t/
+The "test.third" leaves a lot of files named F<foo_bar.3log> in the t/
subdirectory. There is a problem with these files: Third Degree is so
effective that it finds problems also in the system libraries.
-Therefore there are certain types of errors that you should ignore in
-your debugging. Errors with stack traces matching
-
- __actual_atof|__catgets|_doprnt|__exc_|__exec|_findio|__localtime|setlocale|__sia_|__strxfrm
-
-(all in libc.so) are known to be non-serious. You can also
-ignore the combinations
-
- Perl_gv_fetchfile() calling strcpy()
- S_doopen_pmc() calling strcmp()
-
-causing "rih" (reading invalid heap) errors.
+Therefore you should used the Porting/thirdclean script to cleanup
+the F<*.3log> files.
There are also leaks that for given certain definition of a leak,
aren't. See L</PERL_DESTRUCT_LEVEL> for more information.
=head2 PERL_DESTRUCT_LEVEL
-If you want to run any of the tests yourself manually using the
-pureperl or perl.third executables, please note that by default
-perl B<does not> explicitly cleanup all the memory it has allocated
-(such as global memory arenas) but instead lets the exit() of
-the whole program "take care" of such allocations, also known
-as "global destruction of objects".
+If you want to run any of the tests yourself manually using e.g.
+valgrind, or the pureperl or perl.third executables, please note that
+by default perl B<does not> explicitly cleanup all the memory it has
+allocated (such as global memory arenas) but instead lets the exit()
+of the whole program "take care" of such allocations, also known as
+"global destruction of objects".
There is a way to tell perl to do complete cleanup: set the
environment variable PERL_DESTRUCT_LEVEL to a non-zero value.
The t/TEST wrapper does set this to 2, and this is what you
need to do too, if you don't want to see the "global leaks":
+For example, for "third-degreed" Perl:
- PERL_DESTRUCT_LEVEL=2 ./perl.third t/foo/bar.t
+ env PERL_DESTRUCT_LEVEL=2 ./perl.third -Ilib t/foo/bar.t
+
+(Note: the mod_perl apache module uses also this environment variable
+for its own purposes and extended its semantics. Refer to the mod_perl
+documentation for more information. Also, spawned threads do the
+equivalent of setting this variable to the value 1.)
+
+If, at the end of a run you get the message I<N scalars leaked>, you can
+recompile with C<-DDEBUG_LEAKING_SCALARS>, which will cause
+the addresses of all those leaked SVs to be dumped; it also converts
+C<new_SV()> from a macro into a real function, so you can use your
+favourite debugger to discover where those pesky SVs were allocated.
=head2 Profiling
For further information, see your system's manual pages for pixie and prof.
+=head2 Miscellaneous tricks
+
+=over 4
+
+=item *
+
+Those debugging perl with the DDD frontend over gdb may find the
+following useful:
+
+You can extend the data conversion shortcuts menu, so for example you
+can display an SV's IV value with one click, without doing any typing.
+To do that simply edit ~/.ddd/init file and add after:
+
+ ! Display shortcuts.
+ Ddd*gdbDisplayShortcuts: \
+ /t () // Convert to Bin\n\
+ /d () // Convert to Dec\n\
+ /x () // Convert to Hex\n\
+ /o () // Convert to Oct(\n\
+
+the following two lines:
+
+ ((XPV*) (())->sv_any )->xpv_pv // 2pvx\n\
+ ((XPVIV*) (())->sv_any )->xiv_iv // 2ivx
+
+so now you can do ivx and pvx lookups or you can plug there the
+sv_peek "conversion":
+
+ Perl_sv_peek(my_perl, (SV*)()) // sv_peek
+
+(The my_perl is for threaded builds.)
+Just remember that every line, but the last one, should end with \n\
+
+Alternatively edit the init file interactively via:
+3rd mouse button -> New Display -> Edit Menu
+
+Note: you can define up to 20 conversion shortcuts in the gdb
+section.
+
+=item *
+
+If you see in a debugger a memory area mysteriously full of 0xabababab,
+you may be seeing the effect of the Poison() macro, see L<perlclib>.
+
+=back
+
=head2 CONCLUSION
We've had a brief look around the Perl source, an overview of the stages
projects / p5sagit/p5-mst-13.2.git / blobdiff