Rebuilt after backport start for 23674, 23675, and 23676

[p5sagit/p5-mst-13.2.git] / ext / Devel / PPPort / parts / inc / ppphdoc

################################################################################
##
##  $Revision: 17 $
##  $Author: mhx $
##  $Date: 2004/08/13 12:45:56 +0200 $
##
################################################################################
##
##  Version 3.x, Copyright (C) 2004, Marcus Holland-Moritz.
##  Version 2.x, Copyright (C) 2001, Paul Marquess.
##  Version 1.x, Copyright (C) 1999, Kenneth Albanowski.
##
##  This program is free software; you can redistribute it and/or
##  modify it under the same terms as Perl itself.
##
################################################################################

=provides

=dontwarn

NEED_function
NEED_function_GLOBAL
DPPP_NAMESPACE

=implementation

=pod

=head1 NAME

ppport.h - Perl/Pollution/Portability version __VERSION__

=head1 SYNOPSIS

  perl ppport.h [options] [files]

  --help                      show short help

  --patch=file                write one patch file with changes
  --copy=suffix               write changed copies with suffix
  --diff=program              use diff program and options

  --compat-version=version    provide compatibility with Perl version
  --cplusplus                 accept C++ comments

  --quiet                     don't output anything except fatal errors
  --nodiag                    don't show diagnostics
  --nohints                   don't show hints
  --nochanges                 don't suggest changes

  --list-provided             list provided API
  --list-unsupported          list unsupported API

=head1 COMPATIBILITY

This version of F<ppport.h> is designed to support operation with Perl
installations back to __MIN_PERL__, and has been tested up to __MAX_PERL__.

=head1 OPTIONS

=head2 --help

Display a brief usage summary.

=head2 --patch=I<file>

If this option is given, a single patch file will be created if
any changes are suggested. This requires a working diff program
to be installed on your system.

=head2 --copy=I<suffix>

If this option is given, a copy of each file will be saved with
the given suffix that contains the suggested changes. This does
not require any external programs.

If neither C<--patch> or C<--copy> are given, the default is to
simply print the diffs for each file. This requires either
C<Text::Diff> or a C<diff> program to be installed.

=head2 --diff=I<program>

Manually set the diff program and options to use. The default
is to use C<Text::Diff>, when installed, and output unified
context diffs.

=head2 --compat-version=I<version>

Tell F<ppport.h> to check for compatibility with the given
Perl version. The default is to check for compatibility with Perl
version __MIN_PERL__. You can use this option to reduce the output
of F<ppport.h> if you intend to be backward compatible only
up to a certain Perl version.

=head2 --cplusplus

Usually, F<ppport.h> will detect C++ style comments and
replace them with C style comments for portability reasons.
Using this option instructs F<ppport.h> to leave C++
comments untouched.

=head2 --quiet

Be quiet. Don't print anything except fatal errors.

=head2 --nodiag

Don't output any diagnostic messages. Only portability
alerts will be printed.

=head2 --nohints

Don't output any hints. Hints often contain useful portability
notes.

=head2 --nochanges

Don't suggest any changes. Only give diagnostic output and hints
unless these are also deactivated.

=head2 --list-provided

Lists the API elements for which compatibility is provided by
F<ppport.h>. Also lists if it must be explicitly requested,
if it has dependencies, and if there are hints for it.

=head2 --list-unsupported

Lists the API elements that are known not to be supported by
F<ppport.h> and below which version of Perl they probably
won't be available or work.

=head1 DESCRIPTION

In order for a Perl extension (XS) module to be as portable as possible
across differing versions of Perl itself, certain steps need to be taken.

=over 4

=item *

Including this header is the first major one. This alone will give you
access to a large part of the Perl API that hasn't been available in
earlier Perl releases. Use

    perl ppport.h --list-provided

to see which API elements are provided by ppport.h.

=item *

You should avoid using deprecated parts of the API. For example, using
global Perl variables without the C<PL_> prefix is deprecated. Also,
some API functions used to have a C<perl_> prefix. Using this form is
also deprecated. You can safely use the supported API, as F<ppport.h>
will provide wrappers for older Perl versions.

=item *

If you use one of a few functions that were not present in earlier
versions of Perl, and that can't be provided using a macro, you have
to explicitly request support for these functions by adding one or
more C<#define>s in your source code before the inclusion of F<ppport.h>.

These functions will be marked C<explicit> in the list shown by
C<--list-provided>.

Depending on whether you module has a single or multiple files that
use such functions, you want either C<static> or global variants.

For a C<static> function, use:

    #define NEED_function

For a global function, use:

    #define NEED_function_GLOBAL

Note that you mustn't have more than one global request for one
function in your project.

    __EXPLICIT_API__

To avoid namespace conflicts, you can change the namespace of the
explicitly exported functions using the C<DPPP_NAMESPACE> macro.
Just C<#define> the macro before including C<ppport.h>:

    #define DPPP_NAMESPACE MyOwnNamespace_
    #include "ppport.h"

The default namespace is C<DPPP_>.

=back

The good thing is that most of the above can be checked by running
F<ppport.h> on your source code. See the next section for
details.

=head1 EXAMPLES

To verify whether F<ppport.h> is needed for your module, whether you
should make any changes to your code, and whether any special defines
should be used, F<ppport.h> can be run as a Perl script to check your
source code. Simply say:

    perl ppport.h

The result will usually be a list of patches suggesting changes
that should at least be acceptable, if not necessarily the most
efficient solution, or a fix for all possible problems.

If you know that your XS module uses features only available in
newer Perl releases, if you're aware that it uses C++ comments,
and if you want all suggestions as a single patch file, you could
use something like this:

    perl ppport.h --compat-version=5.6.0 --cplusplus --patch=test.diff

If you only want your code to be scanned without any suggestions
for changes, use:

    perl ppport.h --nochanges

You can specify a different C<diff> program or options, using
the C<--diff> option:

    perl ppport.h --diff='diff -C 10'

This would output context diffs with 10 lines of context.

=head1 BUGS

If this version of F<ppport.h> is causing failure during
the compilation of this module, please check if newer versions
of either this module or C<Devel::PPPort> are available on CPAN
before sending a bug report.

If F<ppport.h> was generated using the latest version of
C<Devel::PPPort> and is causing failure of this module, please
file a bug report using the CPAN Request Tracker at L<http://rt.cpan.org/>.

Please include the following information:

=over 4

=item 1.

The complete output from running "perl -V"

=item 2.

This file.

=item 3.

The name and version of the module you were trying to build.

=item 4.

A full log of the build that failed.

=item 5.

Any other information that you think could be relevant.

=back

For the latest version of this code, please get the C<Devel::PPPort>
module from CPAN.

=head1 COPYRIGHT

Version 3.x, Copyright (c) 2004, Marcus Holland-Moritz.

Version 2.x, Copyright (C) 2001, Paul Marquess.

Version 1.x, Copyright (C) 1999, Kenneth Albanowski.

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

=head1 SEE ALSO

See L<Devel::PPPort>.