=head1 NAME
-Pumpkin - Notes on handling the Perl Patch Pumpkin
+Pumpkin - Notes on handling the Perl Patch Pumpkin And Porting Perl
=head1 SYNOPSIS
=head1 DESCRIPTION
-This document attempts to begin to describe some of the
-considerations involved in patching and maintaining perl.
+This document attempts to begin to describe some of the considerations
+involved in patching, porting, and maintaining perl.
This document is still under construction, and still subject to
significant changes. Still, I hope parts of it will be useful,
The Comprehensive Perl Archive Network (or CPAN) is the place to go.
There are many mirrors, but the easiest thing to use is probably
-http://www.perl.com/CPAN, which automatically points you to a
+http://www.cpan.org/README.html , which automatically points you to a
mirror site "close" to you.
=head2 Perl5-porters mailing list
to perl5-porters-request@perl.org .
+Archives of the list are held at:
+
+ http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
+
=head1 How are Perl Releases Numbered?
-Perl version numbers are floating point numbers, such as 5.004. The
-major version number is 5, the minor version is '0', and '03' is the
-patchlevel. The version number is available as the magic variable $],
-and can be used in comparisons, e.g.
+Beginning with v5.6.0, even versions will stand for maintenance releases
+and odd versions for development releases, i.e., v5.6.x for maintenance
+releases, and v5.7.x for development releases. Before v5.6.0, subversions
+_01 through _49 were reserved for bug-fix maintenance releases, and
+subversions _50 through _99 for unstable development versions.
+
+For example, in v5.6.1, the revision number is 5, the version is 6,
+and 1 is the subversion.
- print "You've got an old perl\n" if $] < 5.002;
+For compatibility with the older numbering scheme the composite floating
+point version number continues to be available as the magic variable $],
+and amounts to C<$revision + $version/1000 + $subversion/100000>. This
+can still be used in comparisons.
-(Observations about the imprecision of floating point numbers for
-representing reality probably have more relevance than you might
-imagine :-)
+ print "You've got an old perl\n" if $] < 5.005_03;
-You can also require particular version (or later) with
+In addition, the version is also available as a string in $^V.
- use 5.002;
+ print "You've got a new perl\n" if $^V and $^V ge v5.6.0;
-=head2 Subversions
+You can also require particular version (or later) with:
-In addition, there may be "developer" sub-versions available. These
-are not official releases. They may contain unstable experimental
-features, and are subject to rapid change. Such developer
-sub-versions are numbered with sub-version numbers. For example,
-version 5.004_04 is the 4'th developer version built on top of
-5.004. It might include the _01, _02, and _03 changes, but it
-also might not. Sub-versions are allowed to be subversive.
+ use 5.006;
-These sub-versions can also be used as floating point numbers, so
-you can do things such as
+or using the new syntax available only from v5.6 onward:
- print "You've got an unstable perl\n" if $] == 5.00403;
+ use v5.6.0;
-You can also require particular version (or later) with
+At some point in the future, we may need to decide what to call the
+next big revision. In the .package file used by metaconfig to
+generate Configure, there are two variables that might be relevant:
+$baserev=5 and $package=perl5.
+
+Perl releases produced by the members of perl5-porters are usually
+available on CPAN in the F<src/5.0/maint> and F<src/5.0/devel>
+directories.
- use 5.004_03; # the "_" is optional
+=head2 Maintenance and Development Subversions
-Sub-versions produced by the members of perl5-porters are usually
-available on CPAN in the F<src/5.0/unsupported> directory.
+The first rule of maintenance work is "First, do no harm."
-=head2 Why such a complicated scheme?
+Trial releases of bug-fix maintenance releases are announced on
+perl5-porters. Trial releases use the new subversion number (to avoid
+testers installing it over the previous release) and include a 'local
+patch' entry in patchlevel.h. The distribution file contains the
+string C<MAINT_TRIAL> to make clear that the file is not meant for
+public consumption.
-Two reasons, really. At least.
+In general, the names of official distribution files for the public
+always match the regular expression:
-First, we need some way to identify releases that are known to
-have new features that need testing and exploration. The
-subversion scheme does that nicely while fitting into the
-C<use 5.004;> mold.
+ ^perl\d+\.(\d+)\.\d+(-MAINT_TRIAL_\d+)\.tar\.gz$
-Second, since most of the folks who help maintain perl do so on a
-free-time voluntary basis, perl development does not proceed at a
-precise pace, though it always seems to be moving ahead quickly.
-We needed some way to pass around the "patch pumpkin" to allow
-different people chances to work on different aspects of the
-distribution without getting in each other's way. It wouldn't be
-constructive to have multiple people working on incompatible
-implementations of the same idea. Instead what was needed was
-some kind of "baton" or "token" to pass around so everyone knew
-whose turn was next.
+C<$1> in the pattern is always an even number for maintenance
+versions, and odd for developer releases.
+
+In the past it has been observed that pumpkings tend to invent new
+naming conventions on the fly. If you are a pumpking, before you
+invent a new name for any of the three types of perl distributions,
+please inform the guys from the CPAN who are doing indexing and
+provide the trees of symlinks and the like. They will have to know
+I<in advance> what you decide.
=head2 Why is it called the patch pumpkin?
The name has stuck.
-=head1 Philosophical Issues in Patching Perl
+=head1 Philosophical Issues in Patching and Porting Perl
There are no absolute rules, but there are some general guidelines I
have tried to follow as I apply patches to the perl sources.
=head2 Solve problems as generally as possible
-(I still have to think of a good example here.)
+Never implement a specific restricted solution to a problem when you
+can solve the same problem in a more general, flexible way.
+
+For example, for dynamic loading to work on some SVR4 systems, we had
+to build a shared libperl.so library. In order to build "FAT" binaries
+on NeXT 4.0 systems, we had to build a special libperl library. Rather
+than continuing to build a contorted nest of special cases, I
+generalized the process of building libperl so that NeXT and SVR4 users
+could still get their work done, but others could build a shared
+libperl if they wanted to as well.
+
+Contain your changes carefully. Assume nothing about other operating
+systems, not even closely related ones. Your changes must not affect
+other platforms.
+
+Spy shamelessly on how similar patching or porting issues have been
+settled elsewhere.
+
+If feasible, try to keep filenames 8.3-compliant to humor those poor
+souls that get joy from running Perl under such dire limitations.
+There's a script, check83.pl, for keeping your nose 8.3-clean.
+In a similar vein, do not create files or directories which differ only
+in case (upper versus lower).
=head2 Seek consensus on major changes
check all the files F<pod/*.pod> and also the F<INSTALL> document.
Consider writing the appropriate documentation first and then
-implementing it to correspond to the documentation.
+implementing your change to correspond to the documentation.
=head2 Avoid machine-specific #ifdef's
releases of the operating system. Further, the feature-specific tests
may help out folks on another platform who have the same problem.
+=head2 Machine-specific files
+
+=over 4
+
+=item source code
+
+If you have many machine-specific #defines or #includes, consider
+creating an "osish.h" (os2ish.h, vmsish.h, and so on) and including
+that in perl.h. If you have several machine-specific files (function
+emulations, function stubs, build utility wrappers) you may create a
+separate subdirectory (djgpp, win32) and put the files in there.
+Remember to update C<MANIFEST> when you add files.
+
+If your system supports dynamic loading but none of the existing
+methods at F<ext/DynaLoader/dl_*.xs> work for you, you must write
+a new one. Study the existing ones to see what kind of interface
+you must supply.
+
+=item build hints
+
+There are two kinds of hints: hints for building Perl and hints for
+extensions. The former live in the C<hints> subdirectory, the latter
+in C<ext/*/hints> subdirectories.
+
+The top level hints are Bourne-shell scripts that set, modify and
+unset appropriate Configure variables, based on the Configure command
+line options and possibly existing config.sh and Policy.sh files from
+previous Configure runs.
+
+The extension hints are written in Perl (by the time they are used
+miniperl has been built) and control the building of their respective
+extensions. They can be used to for example manipulate compilation
+and linking flags.
+
+=item build and installation Makefiles, scripts, and so forth
+
+Sometimes you will also need to tweak the Perl build and installation
+procedure itself, like for example F<Makefile.SH> and F<installperl>.
+Tread very carefully, even more than usual. Contain your changes
+with utmost care.
+
+=item test suite
+
+Many of the tests in C<t> subdirectory assume machine-specific things
+like existence of certain functions, something about filesystem
+semantics, certain external utilities and their error messages. Use
+the C<$^O> and the C<Config> module (which contains the results of the
+Configure run, in effect the C<config.sh> converted to Perl) to either
+skip (preferably not) or customize (preferable) the tests for your
+platform.
+
+=item modules
+
+Certain standard modules may need updating if your operating system
+sports for example a native filesystem naming. You may want to update
+some or all of the modules File::Basename, File::Spec, File::Path, and
+File::Copy to become aware of your native filesystem syntax and
+peculiarities.
+
+Remember to have a $VERSION in the modules. You can use the
+Porting/checkVERSION.pl script for checking this.
+
+=item documentation
+
+If your operating system comes from outside UNIX you almost certainly
+will have differences in the available operating system functionality
+(missing system calls, different semantics, whatever). Please
+document these at F<pod/perlport.pod>. If your operating system is
+the first B<not> to have a system call also update the list of
+"portability-bewares" at the beginning of F<pod/perlfunc.pod>.
+
+A file called F<README.youros> at the top level that explains things
+like how to install perl at this platform, where to get any possibly
+required additional software, and for example what test suite errors
+to expect, is nice too. Such files are in the process of being written
+in pod format and will eventually be renamed F<INSTALL.youros>.
+
+You may also want to write a separate F<.pod> file for your operating
+system to tell about existing mailing lists, os-specific modules,
+documentation, whatever. Please name these along the lines of
+F<perl>I<youros>.pod. [unfinished: where to put this file (the pod/
+subdirectory, of course: but more importantly, which/what index files
+should be updated?)]
+
+=back
+
=head2 Allow for lots of testing
We should never release a main version without testing it as a
subversion first.
-=head2 Automate generatation of derivative files
+=head2 Test popular applications and modules.
+
+We should never release a main version without testing whether or not
+it breaks various popular modules and applications. A partial list of
+such things would include majordomo, metaconfig, apache, Tk, CGI,
+libnet, and libwww, to name just a few. Of course it's quite possible
+that some of those things will be just plain broken and need to be fixed,
+but, in general, we ought to try to avoid breaking widely-installed
+things.
+
+=head2 Automated generation of derivative files
The F<embed.h>, F<keywords.h>, F<opcode.h>, and F<perltoc.pod> files
are all automatically generated by perl scripts. In general, don't
F<Configure> and F<config_h.SH> are also automatically generated by
B<metaconfig>. In general, you should patch the metaconfig units
-instead of patching these files directly. However, minor changes to
-F<Configure> may be made in between major sync-ups with the metaconfig
-units, which tends to be complicated operations.
+instead of patching these files directly. However, very minor changes
+to F<Configure> may be made in between major sync-ups with the
+metaconfig units, which tends to be complicated operations. But be
+careful, this can quickly spiral out of control. Running metaconfig
+is not really hard.
+
+Also F<Makefile> is automatically produced from F<Makefile.SH>.
+In general, look out for all F<*.SH> files.
+
+Finally, the sample files in the F<Porting/> subdirectory are
+generated automatically by the script F<U/mksample> included
+with the metaconfig units. See L<"run metaconfig"> below for
+information on obtaining the metaconfig units.
=head1 How to Make a Distribution
Here are the steps I go through to prepare a patch & distribution.
-Lots of it could doubtless be automated but isn't.
+Lots of it could doubtless be automated but isn't. The Porting/makerel
+(make release) perl script does now help automate some parts of it.
=head2 Announce your intentions
she has the pumpkin, but there might also be larger issues at stake.
One of the precepts of the subversion idea is that we shouldn't give
-it to anyone unless we have some idea what you're going to do with
-it.
+the patch pumpkin to anyone unless we have some idea what he or she
+is going to do with it.
=head2 refresh pod/perltoc.pod
changed any documentation in any module or pod file, change to the
F<pod> directory and run C<make toc>.
+=head2 run installhtml to check the validity of the pod files
+
=head2 update patchlevel.h
Don't be shy about using the subversion number, even for a relatively
incorporate that feedback quickly (e.g. within 1 week) and send out a
second patch.
+If you update the subversion number, you may need to change the version
+number near the top of the F<Changes> file.
+
=head2 run metaconfig
If you need to make changes to Configure or config_h.SH, it may be best to
metaconfig -m
-will regenerate Configure and config_h.SH. More information on
-obtaining and running metaconfig is in the F<U/README> file that comes
-with Perl's metaconfig units. Perl's metaconfig units should be
-available the same place you found this file. On CPAN, look under my
-directory F<id/ANDYD/> for a file such as F<5.003_07-02.U.tar.gz>.
-That file should be unpacked in your main perl source directory. It
-contains the files needed to run B<metaconfig> to reproduce Perl's
-Configure script.
+will regenerate Configure and config_h.SH. Much more information
+on obtaining and running metaconfig is in the F<U/README> file
+that comes with Perl's metaconfig units. Perl's metaconfig units
+should be available on CPAN. A set of units that will work with
+perl5.005 is in the file F<mc_units-5.005_00-01.tar.gz> under
+http://www.cpan.org/authors/id/ANDYD/ . The mc_units tar file
+should be unpacked in your main perl source directory. Note: those
+units were for use with 5.005. There may have been changes since then.
+Check for later versions or contact perl5-porters@perl.org to obtain a
+pointer to the current version.
Alternatively, do consider if the F<*ish.h> files might be a better
place for your changes.
Make sure the MANIFEST is up-to-date. You can use dist's B<manicheck>
program for this. You can also use
- perl -MExtUtils::Manifest -e fullcheck
-
-to do half the job. This will make sure everything listed in MANIFEST
-is included in the distribution. dist's B<manicheck> command will
-also list extra files in the directory that are not listed in
-MANIFEST.
-
-The MANIFEST is normally sorted, with one exception. Perl includes
-both a F<Configure> script and a F<configure> script. The
-F<configure> script is a front-end to the main F<Configure>, but
-is there to aid folks who use autoconf-generated F<configure> files
-for other software. The problem is that F<Configure> and F<configure>
-are the same on case-insensitive file systems, so I deliberately put
-F<configure> first in the MANIFEST so that the extraction of
-F<Configure> will overwrite F<configure> and leave you with the
-correct script. (The F<configure> script must also have write
-permission for this to work, so it's the only file in the distribution
-I normally have with write permission.)
+ perl -w -MExtUtils::Manifest=fullcheck -e fullcheck
+
+Both commands will also list extra files in the directory that are not
+listed in MANIFEST.
+
+The MANIFEST is normally sorted.
If you are using metaconfig to regenerate Configure, then you should note
that metaconfig actually uses MANIFEST.new, so you want to be sure
All the tests in the t/ directory ought to be executable. The
main makefile used to do a 'chmod t/*/*.t', but that resulted in
a self-modifying distribution--something some users would strongly
-prefer to avoid. Probably, the F<t/TEST> script should check for this
-and do the chmod if needed, but it doesn't currently.
+prefer to avoid. The F<t/TEST> script will check for this
+and do the chmod if needed, but the tests still ought to be
+executable.
In all, the following files should probably be executable:
Configure
configpm
- configure
+ configure.gnu
embed.pl
installperl
installman
keywords.pl
- lib/splain
myconfig
opcode.pl
- perly.fixer
t/TEST
t/*/*.t
*.SH
vms/ext/Stdio/test.pl
vms/ext/filespec.t
- vms/fndvers.com
x2p/*.SH
Other things ought to be readable, at least :-).
=head2 Run Configure
This will build a config.sh and config.h. You can skip this if you haven't
-changed Configure or config_h.SH at all.
-
-=head2 Update config_H
-
-The config_H file is provided to help those folks who can't run Configure.
-It is important to keep it up-to-date. If you have changed config_h.SH,
-those changes must be reflected in config_H as well. (The name config_H was
-chosen to distinguish the file from config.h even on case-insensitive file
-systems.) Simply edit the existing config_H file; keep the first few
-explanatory lines and then copy your new config.h below.
-
-It may also be necessary to update vms/config.vms and
+changed Configure or config_h.SH at all. I use the following command
+
+ sh Configure -Dprefix=/opt/perl -Doptimize=-O -Dusethreads \
+ -Dcf_by='yourname' \
+ -Dcf_email='yourname@yourhost.yourplace.com' \
+ -Dperladmin='yourname@yourhost.yourplace.com' \
+ -Dmydomain='.yourplace.com' \
+ -Dmyhostname='yourhost' \
+ -des
+
+=head2 Update Porting/config.sh and Porting/config_H
+
+[XXX
+This section needs revision. We're currently working on easing
+the task of keeping the vms, win32, and plan9 config.sh info
+up-to-date. The plan is to use keep up-to-date 'canned' config.sh
+files in the appropriate subdirectories and then generate 'canned'
+config.h files for vms, win32, etc. from the generic config.sh file.
+This is to ease maintenance. When Configure gets updated, the parts
+sometimes get scrambled around, and the changes in config_H can
+sometimes be very hard to follow. config.sh, on the other hand, can
+safely be sorted, so it's easy to track (typically very small) changes
+to config.sh and then propagate them to a canned 'config.h' by any
+number of means, including a perl script in win32/ or carrying
+config.sh and config_h.SH to a Unix system and running sh
+config_h.SH.) Vms uses configure.com to generate its own config.sh
+and config.h. If you want to add a new variable to config.sh check
+with vms folk how to add it to configure.com too.
+XXX]
+
+The Porting/config.sh and Porting/config_H files are provided to
+help those folks who can't run Configure. It is important to keep
+them up-to-date. If you have changed config_h.SH, those changes must
+be reflected in config_H as well. (The name config_H was chosen to
+distinguish the file from config.h even on case-insensitive file systems.)
+Simply edit the existing config_H file; keep the first few explanatory
+lines and then copy your new config.h below.
+
+It may also be necessary to update win32/config.?c, and
plan9/config.plan9, though you should be quite careful in doing so if
you are not familiar with those systems. You might want to issue your
patch with a promise to quickly issue a follow-up that handles those
directories.
-=head2 make run_byacc
+=head2 make regen_perly
-If you have byacc-1.8.2 (available from CPAN), and if there have been
-changes to F<perly.y>, you can regenerate the F<perly.c> file. The
-run_byacc makefile target does this by running byacc and then applying
-some patches so that byacc dynamically allocates space, rather than
-having fixed limits. This patch is handled by the F<perly.fixer>
-script. Depending on the nature of the changes to F<perly.y>, you may
-or may not have to hand-edit the patch to apply correctly. If you do,
-you should include the edited patch in the new distribution. If you
-have byacc-1.9, the patch won't apply cleanly. Changes to the printf
-output statements mean the patch won't apply cleanly. Long ago I
-started to fix F<perly.fixer> to detect this, but I never completed the
-task.
+If perly.y has been edited, it is necessary to run this target to rebuild
+perly.h, perly.act and perly.tab. In fact this target just runs the Perl
+script regen_perly.pl. Note that perly.c is I<not> rebuilt; this is just a
+plain static file now.
-Some additional notes from Larry on this:
+This target relies on you having Bison installed on your system. Running
+the target will tell you if you haven't got the right version, and if so,
+where to get the right one. Or if you prefer, you could hack
+regen_perly.pl to work with your version of Bison. The important things
+are that the regexes can still extract out the right chunks of the Bison
+output into perly.act and perly.tab, and that the contents of those two
+files, plus perly.h, are functionally equivalent to those produced by the
+supported version of Bison.
-Don't forget to regenerate perly.c.diff.
+Note that in the old days, you had to do C<make run_byacc> instead.
- byacc perly.y
- mv y.tab.c perly.c
- patch perly.c <perly.c.diff
- # manually apply any failed hunks
- diff -c2 perly.c.orig perly.c >perly.c.diff
+=head2 make regen_all
-One chunk of lines that often fails begins with
-
- #line 29 "perly.y"
-
-and ends one line before
-
- #define YYERRCODE 256
-
-This only happens when you add or remove a token type. I suppose this
-could be automated, but it doesn't happen very often nowadays.
-
-Larry
+This target takes care of the regen_headers, and regen_pods targets.
=head2 make regen_headers
- perl keywords.pl
-However, I got lots of mail consisting of people worrying because the
+However, I got B<lots> of mail consisting of people worrying because the
command failed. I eventually decided that I would save myself time
and effort by manually running C<make regen_headers> myself rather
than answering all the questions and complaints about the failing
command.
-=head2 global.sym and interp.sym
+=head2 make regen_pods
+
+Will run `make regen_pods` in the pod directory for indexing.
+
+=head2 global.sym, interp.sym and perlio.sym
Make sure these files are up-to-date. Read the comments in these
files and in perl_exp.SH to see what to do.
If you do change F<global.sym> or F<interp.sym>, think carefully about
what you are doing. To the extent reasonable, we'd like to maintain
-souce and binary compatibility with older releases of perl. That way,
+source and binary compatibility with older releases of perl. That way,
extensions built under one version of perl will continue to work with
new versions of perl.
backwards-compatibility stubs. There's a lot of XS code out there.
Let's not force people to keep changing it.
+=head2 PPPort
+
+F<ext/Devel/PPPort/PPPort.pm> needs to be synchronized to include all
+new macros added to .h files (normally perl.h and XSUB.h, but others
+as well). Since chances are that when a new macro is added the
+committer will forget to update F<PPPort.pm>, it's the best to diff for
+changes in .h files when making a new release and making sure that
+F<PPPort.pm> contains them all.
+
+The pumpking can delegate the synchronization responsibility to anybody
+else, but the release process is the only place where we can make sure
+that no new macros fell through the cracks.
+
=head2 Changes
Be sure to update the F<Changes> file. Try to include both an overall
summary as well as detailed descriptions of the changes. Your
-audience will include bother developers and users, so describe
+audience will include other developers and users, so describe
user-visible changes (if any) in terms they will understand, not in
code like "initialize foo variable in bar function".
separately in the patch file (or both). There is no disagreement that
detailed descriptions ought to be easily available somewhere.
+If you update the subversion number in F<patchlevel.h>, you may need
+to change the version number near the top of the F<Changes> file.
+
+=head2 Todo
+
+The F<pod/perltodo.pod> file contains a roughly-categorized unordered
+list of aspects of Perl that could use enhancement, features that could
+be added, areas that could be cleaned up, and so on. During your term
+as pumpkin-holder, you will probably address some of these issues, and
+perhaps identify others which, while you decide not to address them this
+time around, may be tackled in the future. Update the file to reflect
+the situation as it stands when you hand over the pumpkin.
+
+You might like, early in your pumpkin-holding career, to see if you
+can find champions for particular issues on the to-do list: an issue
+owned is an issue more likely to be resolved.
+
+There are also some more porting-specific L</Todo> items later in this
+file.
+
=head2 OS/2-specific updates
In the os2 directory is F<diff.configure>, a set of OS/2-specific
want to consider regenerating this diff file to save trouble for the
OS/2 maintainer.
-=head2 VMS-specific updates
+You can also consider the OS/2 diffs as reminders of portability
+things that need to be fixed in Configure.
-If you have changed F<perly.y>, then you may want to update
-F<vms/perly_{h,c}.vms> by running C<perl vms/vms_yfix.pl>.
+=head2 VMS-specific updates
-The Perl version number appears in several places under F<vms>.
-It is courteous to update these versions. For example, if you are
-making 5.004_42, replace "5.00441" with "5.00442".
+The Perl revision number appears as "perl5" in configure.com.
+It is courteous to update that if necessary.
=head2 Making the new distribution
tar cf perl5.004_08.tar perl5.004_08
gzip --best perl5.004_08.tar
+These steps, with extra checks, are automated by the Porting/makerel
+script.
+
=head2 Making a new patch
I find the F<makepatch> utility quite handy for making patches.
You can obtain it from any CPAN archive under
-http://www.perl.com/CPAN/authors/Johan_Vromans/. The only
-difference between my version and the standard one is that I have mine
-do a
+http://www.cpan.org/authors/Johan_Vromans/ . There are a couple
+of differences between my version and the standard one. I have mine do
+a
# Print a reassuring "End of Patch" note so people won't
# wonder if their mailer truncated patches.
print "\n\nEnd of Patch.\n";
-at the end. That's because I used to get questions from people asking if
-their mail was truncated.
+at the end. That's because I used to get questions from people asking
+if their mail was truncated.
+
+It also writes Index: lines which include the new directory prefix
+(change Index: print, approx line 294 or 310 depending on the version,
+to read: print PATCH ("Index: $newdir$new\n");). That helps patches
+work with more POSIX conformant patch programs.
Here's how I generate a new patch. I'll use the hypothetical
5.004_07 to 5.004_08 patch as an example.
of perl5.004_08.pat, leaving just the shell commands. Then, I do the
following:
- cd perl5.003_07
- sh ../perl5.003_08.pat
+ cd perl5.004_07
+ sh ../perl5.004_08.pat
cd ..
- makepatch perl5.003_07 perl5.003_08 >> perl5.003_08.pat
+ makepatch perl5.004_07 perl5.004_08 >> perl5.004_08.pat
(Note the append to preserve my shell commands.)
Now, my patch will line up with what the end users are going to do.
It seems obvious, but be sure to test your patch. That is, verify that
it produces exactly the same thing as your full distribution.
- rm -rf perl5.003_07
- gzip -d -c perl5.003_07.tar.gz | tar -xf -
- cd perl5.003_07
- sh ../perl5.003_08.pat
- patch -p1 -N < ../perl5.003_08.pat
+ rm -rf perl5.004_07
+ gzip -d -c perl5.004_07.tar.gz | tar -xf -
+ cd perl5.004_07
+ sh ../perl5.004_08.pat
+ patch -p1 -N < ../perl5.004_08.pat
cd ..
- gdiff -r perl5.003_07 perl5.003_08
+ gdiff -r perl5.004_07 perl5.004_08
where B<gdiff> is GNU diff. Other diff's may also do recursive checking.
You can also hand-tweak your config.h to try out different #ifdef
branches.
-=head1 Common Gotcha's
+=head2 Other tests
+
+=over 4
+
+=item gcc -ansi -pedantic
+
+Configure -Dgccansipedantic [ -Dcc=gcc ] will enable (via the cflags script,
+not $Config{ccflags}) the gcc strict ANSI C flags -ansi and -pedantic for
+the compilation of the core files on platforms where it knows it can
+do so (like Linux, see cflags.SH for the full list), and on some
+platforms only one (Solaris can do only -pedantic, not -ansi).
+The flag -DPERL_GCC_PEDANTIC also gets added, since gcc does not add
+any internal cpp flag to signify that -pedantic is being used, as it
+does for -ansi (__STRICT_ANSI__).
+
+Note that the -ansi and -pedantic are enabled only for version 3 (and
+later) of gcc, since even gcc version 2.95.4 finds lots of seemingly
+false "value computed not used" errors from Perl.
+
+The -ansi and -pedantic are useful in catching at least the following
+nonportable practices:
+
+=over 4
+
+=item *
+
+gcc-specific extensions
+
+=item *
+
+lvalue casts
+
+=item *
+
+// C++ comments
+
+=item *
+
+enum trailing commas
+
+=back
+
+The -Dgccansipedantic should be used only when cleaning up the code,
+not for production builds, since otherwise gcc cannot inline certain
+things.
+
+=back
+
+=head1 Running Purify
+
+Purify is a commercial tool that is helpful in identifying memory
+overruns, wild pointers, memory leaks and other such badness. Perl
+must be compiled in a specific way for optimal testing with Purify.
+
+Use the following commands to test perl with Purify:
+
+ sh Configure -des -Doptimize=-g -Uusemymalloc -Dusemultiplicity \
+ -Accflags=-DPURIFY
+ setenv PURIFYOPTIONS "-chain-length=25"
+ make all pureperl
+ cd t
+ ln -s ../pureperl perl
+ setenv PERL_DESTRUCT_LEVEL 2
+ ./perl TEST
+
+Disabling Perl's malloc allows Purify to monitor allocations and leaks
+more closely; using Perl's malloc will make Purify report most leaks
+in the "potential" leaks category. Enabling the multiplicity option
+allows perl to clean up thoroughly when the interpreter shuts down, which
+reduces the number of bogus leak reports from Purify. The -DPURIFY
+enables any Purify-specific debugging code in the sources.
+
+Purify outputs messages in "Viewer" windows by default. If you don't have
+a windowing environment or if you simply want the Purify output to
+unobtrusively go to a log file instead of to the interactive window,
+use the following options instead:
+
+ setenv PURIFYOPTIONS "-chain-length=25 -windows=no -log-file=perl.log \
+ -append-logfile=yes"
+
+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.)
+
+=head1 Common Gotchas
=over 4
=item Metaconfig worked for me
-My system at the time was Interactive 2.2, a SVR3.2/386 derivative that
+My system at the time was Interactive 2.2, an SVR3.2/386 derivative that
also had some POSIX support. Metaconfig-generated Configure scripts
worked fine for me on that system. On the other hand, autoconf-generated
scripts usually didn't. (They did come quite close, though, in some
=back
-=head2 @INC search order
-
-By default, the list of perl library directories in @INC is the
-following:
-
- $archlib
- $privlib
- $sitearch
- $sitelib
-
-Specifically, on my Solaris/x86 system, I run
-B<sh Configure -Dprefix=/opt/perl> and I have the following
-directories:
-
- /opt/perl/lib/i86pc-solaris/5.00307
- /opt/perl/lib
- /opt/perl/lib/site_perl/i86pc-solaris
- /opt/perl/lib/site_perl
-
-That is, perl's directories come first, followed by the site-specific
-directories.
-
-The site libraries come second to support the usage of extensions
-across perl versions. Read the relevant section in F<INSTALL> for
-more information. If we ever make $sitearch version-specific, this
-topic could be revisited.
-
=head2 Why isn't there a directory to override Perl's library?
Mainly because no one's gotten around to making one. Note that
probably have been named something to do with overriding though. Since
it's undocumented we could still change it... :-)
-Given that it's already there, you can use it to override
-distribution modules. If you do
+Given that it's already there, you can use it to override distribution modules.
+One way to do that is to add
+
+ ccflags="$ccflags -DAPPLLIB_EXP=\"/my/override\""
+
+to your config.over file. (You have to be particularly careful to get the
+double quotes in. APPLLIB_EXP must be a valid C string. It might
+actually be easier to just #define it yourself in perl.c.)
+
+Then perl.c will put /my/override ahead of ARCHLIB and PRIVLIB. Perl will
+also search architecture-specific and version-specific subdirectories of
+APPLLIB_EXP.
+
+=head2 Shared libperl.so location
+
+Why isn't the shared libperl.so installed in /usr/lib/ along
+with "all the other" shared libraries? Instead, it is installed
+in $archlib, which is typically something like
+
+ /usr/local/lib/perl5/archname/5.00404
+
+and is architecture- and version-specific.
+
+The basic reason why a shared libperl.so gets put in $archlib is so that
+you can have more than one version of perl on the system at the same time,
+and have each refer to its own libperl.so.
+
+Three examples might help. All of these work now; none would work if you
+put libperl.so in /usr/lib.
+
+=over
+
+=item 1.
+
+Suppose you want to have both threaded and non-threaded perl versions
+around. Configure will name both perl libraries "libperl.so" (so that
+you can link to them with -lperl). The perl binaries tell them apart
+by having looking in the appropriate $archlib directories.
+
+=item 2.
+
+Suppose you have perl5.004_04 installed and you want to try to compile
+it again, perhaps with different options or after applying a patch.
+If you already have libperl.so installed in /usr/lib/, then it may be
+either difficult or impossible to get ld.so to find the new libperl.so
+that you're trying to build. If, instead, libperl.so is tucked away in
+$archlib, then you can always just change $archlib in the current perl
+you're trying to build so that ld.so won't find your old libperl.so.
+(The INSTALL file suggests you do this when building a debugging perl.)
+
+=item 3.
+
+The shared perl library is not a "well-behaved" shared library with
+proper major and minor version numbers, so you can't necessarily
+have perl5.004_04 and perl5.004_05 installed simultaneously. Suppose
+perl5.004_04 were to install /usr/lib/libperl.so.4.4, and perl5.004_05
+were to install /usr/lib/libperl.so.4.5. Now, when you try to run
+perl5.004_04, ld.so might try to load libperl.so.4.5, since it has
+the right "major version" number. If this works at all, it almost
+certainly defeats the reason for keeping perl5.004_04 around. Worse,
+with development subversions, you certaily can't guarantee that
+libperl.so.4.4 and libperl.so.4.55 will be compatible.
+
+Anyway, all this leads to quite obscure failures that are sure to drive
+casual users crazy. Even experienced users will get confused :-). Upon
+reflection, I'd say leave libperl.so in $archlib.
+
+=back
+
+=head2 Indentation style
- sh Configure -Dccflags='-DAPPLLIB_EXP=/my/override'
+Over the years Perl has become a mishmash of
+various indentation styles, but the original "Larry style" can
+probably be restored with (GNU) indent somewhat like this:
-then perl.c will put /my/override ahead of ARCHLIB and PRIVLIB.
+ indent -kr -nce -psl -sc
+
+A more ambitious solution would also specify a list of Perl specific
+types with -TSV -TAV -THV .. -TMAGIC -TPerlIO ... but that list would
+be quite ungainly. Also note that GNU indent also doesn't do aligning
+of consecutive assignments, which would truly wreck the layout in
+places like sv.c:Perl_sv_upgrade() or sv.c:Perl_clone_using().
+Similarly nicely aligned &&s, ||s and ==s would not be respected.
=head1 Upload Your Work to CPAN
You can upload your work to CPAN if you have a CPAN id. Check out
-http://www.perl.com/CPAN/modules/04pause.html for information on
+http://www.cpan.org/modules/04pause.html for information on
_PAUSE_, the Perl Author's Upload Server.
I typically upload both the patch file, e.g. F<perl5.004_08.pat.gz>
If you want your patch to appear in the F<src/5.0/unsupported>
directory on CPAN, send e-mail to the CPAN master librarian. (Check
-out http://www.perl.com/CPAN/CPAN.html).
+out http://www.cpan.org/CPAN.html ).
=head1 Help Save the World
items that merit consideration. This list isn't exhaustive, it's just
what I came up with off the top of my head.
-=head2 Good ideas waiting for round tuits
-
-=over 4
-
-=item installprefix
+=head2 Adding missing library functions to Perl
+
+The perl Configure script automatically determines which headers and
+functions you have available on your system and arranges for them to be
+included in the compilation and linking process. Occasionally, when porting
+perl to an operating system for the first time, you may find that the
+operating system is missing a key function. While perl may still build
+without this function, no perl program will be able to reference the missing
+function. You may be able to write the missing function yourself, or you
+may be able to find the missing function in the distribution files for
+another software package. In this case, you need to instruct the perl
+configure-and-build process to use your function. Perform these steps.
+
+=over 3
+
+=item *
+
+Code and test the function you wish to add. Test it carefully; you will
+have a much easier time debugging your code independently than when it is a
+part of perl.
+
+=item *
+
+Here is an implementation of the POSIX truncate function for an operating
+system (VOS) that does not supply one, but which does supply the ftruncate()
+function.
+
+ /* Beginning of modification history */
+ /* Written 02-01-02 by Nick Ing-Simmons (nick@ing-simmons.net) */
+ /* End of modification history */
+
+ /* VOS doesn't supply a truncate function, so we build one up
+ from the available POSIX functions. */
+
+ #include <fcntl.h>
+ #include <sys/types.h>
+ #include <unistd.h>
+
+ int
+ truncate(const char *path, off_t len)
+ {
+ int fd = open(path,O_WRONLY);
+ int code = -1;
+ if (fd >= 0) {
+ code = ftruncate(fd,len);
+ close(fd);
+ }
+ return code;
+ }
+
+Place this file into a subdirectory that has the same name as the operating
+system. This file is named perl/vos/vos.c
+
+=item *
+
+If your operating system has a hints file (in perl/hints/XXX.sh for an
+operating system named XXX), then start with it. If your operating system
+has no hints file, then create one. You can use a hints file for a similar
+operating system, if one exists, as a template.
+
+=item *
+
+Add lines like the following to your hints file. The first line
+(d_truncate="define") instructs Configure that the truncate() function
+exists. The second line (archobjs="vos.o") instructs the makefiles that the
+perl executable depends on the existence of a file named "vos.o". (Make
+will automatically look for "vos.c" and compile it with the same options as
+the perl source code). The final line ("test -h...") adds a symbolic link
+to the top-level directory so that make can find vos.c. Of course, you
+should use your own operating system name for the source file of extensions,
+not "vos.c".
+
+ # VOS does not have truncate() but we supply one in vos.c
+ d_truncate="define"
+ archobjs="vos.o"
+
+ # Help gmake find vos.c
+ test -h vos.c || ln -s vos/vos.c vos.c
+
+The hints file is a series of shell commands that are run in the top-level
+directory (the "perl" directory). Thus, these commands are simply executed
+by Configure at an appropriate place during its execution.
+
+=item *
+
+At this point, you can run the Configure script and rebuild perl. Carefully
+test the newly-built perl to ensure that normal paths, and error paths,
+behave as you expect.
-I think we ought to support
+=back
- Configure -Dinstallprefix=/blah/blah
+=head2 Good ideas waiting for round tuits
-Currently, we support B<-Dprefix=/blah/blah>, but the changing the install
-location has to be handled by something like the F<config.over> trick
-described in F<INSTALL>. AFS users also are treated specially.
-We should probably duplicate the metaconfig prefix stuff for an
-install prefix.
+=over 4
-=item Configure -Dsrcdir=/blah/blah
+=item Configure -Dsrc=/blah/blah
We should be able to emulate B<configure --srcdir>. Tom Tromey
tromey@creche.cygnus.com has submitted some patches to
-the dist-users mailing list along these lines. Eventually, they ought
-to get folded back into the main distribution.
+the dist-users mailing list along these lines. They have been folded
+back into the main distribution, but various parts of the perl
+Configure/build/install process still assume src='.'.
=item Hint file fixes
=over 4
-=item Win95, WinNT, and Win32 support
-
-We need to get something into the distribution for 32-bit Windows.
-I'm tired of all the private e-mail questions I get, and I'm saddened
-that so many folks keep trying to reinvent the same wheel.
-
=item MacPerl
-Get some of the Macintosh stuff folded back into the main
-distribution.
+Get some of the Macintosh stuff folded back into the main distribution.
=item gconvert replacement
Maybe include a replacement function that doesn't lose data in rare
cases of coercion between string and numerical values.
-=item long long
-
-Can we support C<long long> on systems where C<long long> is larger
-than what we've been using for C<IV>? What if you can't C<sprintf>
-a C<long long>?
-
=item Improve makedepend
The current makedepend process is clunky and annoyingly slow, but it
=item File locking
Somehow, straighten out, document, and implement lockf(), flock(),
-and/or fcntl() file locking. It's a mess.
+and/or fcntl() file locking. It's a mess. See $d_fcntl_can_lock
+in recent config.sh files though.
=back
-=head1 AUTHOR
+=head2 Copyright Issues
+
+The following is based on the consensus of a couple of IPR lawyers,
+but it is of course not a legally binding statement, just a common
+sense summary.
+
+=over 4
+
+=item *
+
+Tacking on copyright statements is unnecessary to begin with because
+of the Berne convention. But assuming you want to go ahead...
+
+=item *
+
+The right form of a copyright statement is
+
+ Copyright (C) Year, Year, ... by Someone
+
+The (C) is not required everywhere but it doesn't hurt and in certain
+jurisdictions it is required, so let's leave it in. (Yes, it's true
+that in some jurisdictions the "(C)" is not legally binding, one should
+use the true ringed-C. But we don't have that character available for
+Perl's source code.)
+
+The years must be listed out separately. Year-Year is not correct.
+Only the years when the piece has changed 'significantly' may be added.
+
+=item *
+
+One cannot give away one's copyright trivially. One can give one's
+copyright away by using public domain, but even that requires a little
+bit more than just saying 'this is in public domain'. (What it
+exactly requires depends on your jurisdiction.) But barring public
+domain, one cannot "transfer" one's copyright to another person or
+entity. In the context of software, it means that contributors cannot
+give away their copyright or "transfer" it to the "owner" of the software.
+
+Also remember that in many cases if you are employed by someone,
+your work may be copyrighted to your employer, even when you are
+contributing on your own time (this all depends on too many things
+to list here). But the bottom line is that you definitely can't give
+away a copyright you may not even have.
+
+What is possible, however, is that the software can simply state
+
+ Copyright (C) Year, Year, ... by Someone and others
+
+and then list the "others" somewhere in the distribution.
+And this is exactly what Perl does. (The "somewhere" is
+AUTHORS and the Changes* files.)
+
+=item *
+
+Split files, merged files, and generated files are problematic.
+The rule of thumb: in split files, copy the copyright years of
+the original file to all the new files; in merged files make
+an union of the copyright years of all the old files; in generated
+files propagate the copyright years of the generating file(s).
+
+=item *
+
+The files of Perl source code distribution do carry a lot of
+copyrights, by various people. (There are many copyrights embedded in
+perl.c, for example.) The most straightforward thing for pumpkings to
+do is to simply update Larry's copyrights at the beginning of the
+*.[hcy], x2p/*.[hcy], *.pl, and README files, and leave all other
+copyrights alone. Doing more than that requires quite a bit of tracking.
+
+=back
-Andy Dougherty <doughera@lafcol.lafayette.edu>.
+=head1 AUTHORS
-Additions by Chip Salzenberg <chip@atlantic.net>.
+Original author: Andy Dougherty doughera@lafayette.edu .
+Additions by Chip Salzenberg chip@perl.com and
+Tim Bunce Tim.Bunce@ig.co.uk .
All opinions expressed herein are those of the authorZ<>(s).
=head1 LAST MODIFIED
-$Id: pumpkin.pod,v 1.8 1997/02/18 18:19:20 chip Released $
+$Id: pumpkin.pod,v 1.23 2000/01/13 19:45:13 doughera Released $
https://perl5.git.perl.org / perl5.git / blobdiff