568 lines
15 KiB
Perl
568 lines
15 KiB
Perl
package ExtUtils::Constant;
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use vars qw (@ISA $VERSION @EXPORT_OK %EXPORT_TAGS);
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$VERSION = '0.25';
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=head1 NAME
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ExtUtils::Constant - generate XS code to import C header constants
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=head1 SYNOPSIS
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use ExtUtils::Constant qw (WriteConstants);
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WriteConstants(
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NAME => 'Foo',
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NAMES => [qw(FOO BAR BAZ)],
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);
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# Generates wrapper code to make the values of the constants FOO BAR BAZ
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# available to perl
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=head1 DESCRIPTION
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ExtUtils::Constant facilitates generating C and XS wrapper code to allow
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perl modules to AUTOLOAD constants defined in C library header files.
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It is principally used by the C<h2xs> utility, on which this code is based.
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It doesn't contain the routines to scan header files to extract these
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constants.
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=head1 USAGE
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Generally one only needs to call the C<WriteConstants> function, and then
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#include "const-c.inc"
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in the C section of C<Foo.xs>
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INCLUDE: const-xs.inc
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in the XS section of C<Foo.xs>.
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For greater flexibility use C<constant_types()>, C<C_constant> and
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C<XS_constant>, with which C<WriteConstants> is implemented.
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Currently this module understands the following types. h2xs may only know
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a subset. The sizes of the numeric types are chosen by the C<Configure>
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script at compile time.
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=over 4
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=item IV
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signed integer, at least 32 bits.
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=item UV
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unsigned integer, the same size as I<IV>
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=item NV
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floating point type, probably C<double>, possibly C<long double>
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=item PV
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NUL terminated string, length will be determined with C<strlen>
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=item PVN
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A fixed length thing, given as a [pointer, length] pair. If you know the
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length of a string at compile time you may use this instead of I<PV>
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=item SV
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A B<mortal> SV.
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=item YES
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Truth. (C<PL_sv_yes>) The value is not needed (and ignored).
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=item NO
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Defined Falsehood. (C<PL_sv_no>) The value is not needed (and ignored).
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=item UNDEF
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C<undef>. The value of the macro is not needed.
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=back
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=head1 FUNCTIONS
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=over 4
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=cut
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if ($] >= 5.006) {
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eval "use warnings; 1" or die $@;
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}
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use strict;
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use Carp qw(croak cluck);
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use Exporter;
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use ExtUtils::Constant::Utils qw(C_stringify);
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use ExtUtils::Constant::XS qw(%XS_Constant %XS_TypeSet);
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@ISA = 'Exporter';
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%EXPORT_TAGS = ( 'all' => [ qw(
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XS_constant constant_types return_clause memEQ_clause C_stringify
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C_constant autoload WriteConstants WriteMakefileSnippet
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) ] );
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@EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
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=item constant_types
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A function returning a single scalar with C<#define> definitions for the
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constants used internally between the generated C and XS functions.
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=cut
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sub constant_types {
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ExtUtils::Constant::XS->header();
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}
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sub memEQ_clause {
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cluck "ExtUtils::Constant::memEQ_clause is deprecated";
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ExtUtils::Constant::XS->memEQ_clause({name=>$_[0], checked_at=>$_[1],
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indent=>$_[2]});
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}
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sub return_clause ($$) {
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cluck "ExtUtils::Constant::return_clause is deprecated";
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my $indent = shift;
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ExtUtils::Constant::XS->return_clause({indent=>$indent}, @_);
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}
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sub switch_clause {
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cluck "ExtUtils::Constant::switch_clause is deprecated";
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my $indent = shift;
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my $comment = shift;
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ExtUtils::Constant::XS->switch_clause({indent=>$indent, comment=>$comment},
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@_);
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}
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sub C_constant {
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my ($package, $subname, $default_type, $what, $indent, $breakout, @items)
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= @_;
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ExtUtils::Constant::XS->C_constant({package => $package, subname => $subname,
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default_type => $default_type,
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types => $what, indent => $indent,
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breakout => $breakout}, @items);
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}
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=item XS_constant PACKAGE, TYPES, XS_SUBNAME, C_SUBNAME
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A function to generate the XS code to implement the perl subroutine
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I<PACKAGE>::constant used by I<PACKAGE>::AUTOLOAD to load constants.
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This XS code is a wrapper around a C subroutine usually generated by
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C<C_constant>, and usually named C<constant>.
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I<TYPES> should be given either as a comma separated list of types that the
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C subroutine C<constant> will generate or as a reference to a hash. It should
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be the same list of types as C<C_constant> was given.
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[Otherwise C<XS_constant> and C<C_constant> may have different ideas about
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the number of parameters passed to the C function C<constant>]
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You can call the perl visible subroutine something other than C<constant> if
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you give the parameter I<XS_SUBNAME>. The C subroutine it calls defaults to
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the name of the perl visible subroutine, unless you give the parameter
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I<C_SUBNAME>.
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=cut
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sub XS_constant {
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my $package = shift;
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my $what = shift;
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my $XS_subname = shift;
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my $C_subname = shift;
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$XS_subname ||= 'constant';
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$C_subname ||= $XS_subname;
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if (!ref $what) {
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# Convert line of the form IV,UV,NV to hash
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$what = {map {$_ => 1} split /,\s*/, ($what)};
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}
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my $params = ExtUtils::Constant::XS->params ($what);
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my $type;
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my $xs = <<"EOT";
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void
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$XS_subname(sv)
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PREINIT:
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#ifdef dXSTARG
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dXSTARG; /* Faster if we have it. */
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#else
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dTARGET;
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#endif
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STRLEN len;
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int type;
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EOT
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if ($params->{IV}) {
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$xs .= " IV iv = 0; /* avoid uninit var warning */\n";
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} else {
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$xs .= " /* IV\t\tiv;\tUncomment this if you need to return IVs */\n";
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}
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if ($params->{NV}) {
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$xs .= " NV nv = 0.0; /* avoid uninit var warning */\n";
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} else {
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$xs .= " /* NV\t\tnv;\tUncomment this if you need to return NVs */\n";
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}
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if ($params->{PV}) {
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$xs .= " const char *pv = NULL; /* avoid uninit var warning */\n";
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} else {
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$xs .=
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" /* const char\t*pv;\tUncomment this if you need to return PVs */\n";
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}
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$xs .= << 'EOT';
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INPUT:
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SV * sv;
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const char * s = SvPV(sv, len);
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EOT
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if ($params->{''}) {
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$xs .= << 'EOT';
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INPUT:
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int utf8 = SvUTF8(sv);
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EOT
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}
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$xs .= << 'EOT';
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PPCODE:
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EOT
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if ($params->{IV} xor $params->{NV}) {
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$xs .= << "EOT";
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/* Change this to $C_subname(aTHX_ s, len, &iv, &nv);
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if you need to return both NVs and IVs */
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EOT
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}
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$xs .= " type = $C_subname(aTHX_ s, len";
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$xs .= ', utf8' if $params->{''};
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$xs .= ', &iv' if $params->{IV};
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$xs .= ', &nv' if $params->{NV};
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$xs .= ', &pv' if $params->{PV};
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$xs .= ', &sv' if $params->{SV};
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$xs .= ");\n";
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# If anyone is insane enough to suggest a package name containing %
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my $package_sprintf_safe = $package;
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$package_sprintf_safe =~ s/%/%%/g;
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$xs .= << "EOT";
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/* Return 1 or 2 items. First is error message, or undef if no error.
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Second, if present, is found value */
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switch (type) {
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case PERL_constant_NOTFOUND:
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sv =
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sv_2mortal(newSVpvf("%s is not a valid $package_sprintf_safe macro", s));
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PUSHs(sv);
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break;
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case PERL_constant_NOTDEF:
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sv = sv_2mortal(newSVpvf(
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"Your vendor has not defined $package_sprintf_safe macro %s, used",
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s));
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PUSHs(sv);
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break;
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EOT
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foreach $type (sort keys %XS_Constant) {
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# '' marks utf8 flag needed.
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next if $type eq '';
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$xs .= "\t/* Uncomment this if you need to return ${type}s\n"
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unless $what->{$type};
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$xs .= " case PERL_constant_IS$type:\n";
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if (length $XS_Constant{$type}) {
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$xs .= << "EOT";
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EXTEND(SP, 2);
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PUSHs(&PL_sv_undef);
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$XS_Constant{$type};
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EOT
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} else {
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# Do nothing. return (), which will be correctly interpreted as
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# (undef, undef)
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}
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$xs .= " break;\n";
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unless ($what->{$type}) {
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chop $xs; # Yes, another need for chop not chomp.
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$xs .= " */\n";
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}
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}
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$xs .= << "EOT";
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default:
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sv = sv_2mortal(newSVpvf(
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"Unexpected return type %d while processing $package_sprintf_safe macro %s, used",
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type, s));
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PUSHs(sv);
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}
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EOT
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return $xs;
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}
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=item autoload PACKAGE, VERSION, AUTOLOADER
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A function to generate the AUTOLOAD subroutine for the module I<PACKAGE>
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I<VERSION> is the perl version the code should be backwards compatible with.
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It defaults to the version of perl running the subroutine. If I<AUTOLOADER>
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is true, the AUTOLOAD subroutine falls back on AutoLoader::AUTOLOAD for all
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names that the constant() routine doesn't recognise.
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=cut
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# ' # Grr. syntax highlighters that don't grok pod.
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sub autoload {
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my ($module, $compat_version, $autoloader) = @_;
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$compat_version ||= $];
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croak "Can't maintain compatibility back as far as version $compat_version"
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if $compat_version < 5;
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my $func = "sub AUTOLOAD {\n"
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. " # This AUTOLOAD is used to 'autoload' constants from the constant()\n"
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. " # XS function.";
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$func .= " If a constant is not found then control is passed\n"
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. " # to the AUTOLOAD in AutoLoader." if $autoloader;
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$func .= "\n\n"
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. " my \$constname;\n";
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$func .=
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" our \$AUTOLOAD;\n" if ($compat_version >= 5.006);
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$func .= <<"EOT";
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(\$constname = \$AUTOLOAD) =~ s/.*:://;
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croak "&${module}::constant not defined" if \$constname eq 'constant';
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my (\$error, \$val) = constant(\$constname);
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EOT
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if ($autoloader) {
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$func .= <<'EOT';
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if ($error) {
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if ($error =~ /is not a valid/) {
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$AutoLoader::AUTOLOAD = $AUTOLOAD;
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goto &AutoLoader::AUTOLOAD;
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} else {
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croak $error;
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}
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}
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EOT
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} else {
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$func .=
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" if (\$error) { croak \$error; }\n";
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}
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$func .= <<'END';
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{
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no strict 'refs';
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# Fixed between 5.005_53 and 5.005_61
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#XXX if ($] >= 5.00561) {
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#XXX *$AUTOLOAD = sub () { $val };
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#XXX }
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#XXX else {
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*$AUTOLOAD = sub { $val };
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#XXX }
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}
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goto &$AUTOLOAD;
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}
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END
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return $func;
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}
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=item WriteMakefileSnippet
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WriteMakefileSnippet ATTRIBUTE =E<gt> VALUE [, ...]
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A function to generate perl code for Makefile.PL that will regenerate
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the constant subroutines. Parameters are named as passed to C<WriteConstants>,
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with the addition of C<INDENT> to specify the number of leading spaces
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(default 2).
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Currently only C<INDENT>, C<NAME>, C<DEFAULT_TYPE>, C<NAMES>, C<C_FILE> and
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C<XS_FILE> are recognised.
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=cut
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sub WriteMakefileSnippet {
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my %args = @_;
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my $indent = $args{INDENT} || 2;
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my $result = <<"EOT";
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ExtUtils::Constant::WriteConstants(
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NAME => '$args{NAME}',
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NAMES => \\\@names,
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DEFAULT_TYPE => '$args{DEFAULT_TYPE}',
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EOT
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foreach (qw (C_FILE XS_FILE)) {
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next unless exists $args{$_};
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$result .= sprintf " %-12s => '%s',\n",
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$_, $args{$_};
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}
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$result .= <<'EOT';
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);
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EOT
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$result =~ s/^/' 'x$indent/gem;
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return ExtUtils::Constant::XS->dump_names({default_type=>$args{DEFAULT_TYPE},
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indent=>$indent,},
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@{$args{NAMES}})
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. $result;
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}
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=item WriteConstants ATTRIBUTE =E<gt> VALUE [, ...]
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Writes a file of C code and a file of XS code which you should C<#include>
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and C<INCLUDE> in the C and XS sections respectively of your module's XS
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code. You probably want to do this in your C<Makefile.PL>, so that you can
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easily edit the list of constants without touching the rest of your module.
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The attributes supported are
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=over 4
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=item NAME
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Name of the module. This must be specified
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=item DEFAULT_TYPE
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The default type for the constants. If not specified C<IV> is assumed.
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=item BREAKOUT_AT
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The names of the constants are grouped by length. Generate child subroutines
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for each group with this number or more names in.
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=item NAMES
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An array of constants' names, either scalars containing names, or hashrefs
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as detailed in L<"C_constant">.
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=item PROXYSUBS
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If true, uses proxy subs. See L<ExtUtils::Constant::ProxySubs>.
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=item C_FH
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A filehandle to write the C code to. If not given, then I<C_FILE> is opened
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for writing.
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=item C_FILE
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The name of the file to write containing the C code. The default is
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C<const-c.inc>. The C<-> in the name ensures that the file can't be
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mistaken for anything related to a legitimate perl package name, and
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not naming the file C<.c> avoids having to override Makefile.PL's
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C<.xs> to C<.c> rules.
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=item XS_FH
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A filehandle to write the XS code to. If not given, then I<XS_FILE> is opened
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for writing.
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=item XS_FILE
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The name of the file to write containing the XS code. The default is
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C<const-xs.inc>.
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=item XS_SUBNAME
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The perl visible name of the XS subroutine generated which will return the
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constants. The default is C<constant>.
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=item C_SUBNAME
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The name of the C subroutine generated which will return the constants.
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The default is I<XS_SUBNAME>. Child subroutines have C<_> and the name
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length appended, so constants with 10 character names would be in
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C<constant_10> with the default I<XS_SUBNAME>.
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=back
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=cut
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sub WriteConstants {
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my %ARGS =
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( # defaults
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C_FILE => 'const-c.inc',
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XS_FILE => 'const-xs.inc',
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XS_SUBNAME => 'constant',
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DEFAULT_TYPE => 'IV',
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@_);
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$ARGS{C_SUBNAME} ||= $ARGS{XS_SUBNAME}; # No-one sane will have C_SUBNAME eq '0'
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croak "Module name not specified" unless length $ARGS{NAME};
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# Do this before creating (empty) files, in case it fails:
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require ExtUtils::Constant::ProxySubs if $ARGS{PROXYSUBS};
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my $c_fh = $ARGS{C_FH};
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if (!$c_fh) {
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if ($] <= 5.008) {
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# We need these little games, rather than doing things
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# unconditionally, because we're used in core Makefile.PLs before
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# IO is available (needed by filehandle), but also we want to work on
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# older perls where undefined scalars do not automatically turn into
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# anonymous file handles.
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require FileHandle;
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$c_fh = FileHandle->new();
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}
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open $c_fh, ">$ARGS{C_FILE}" or die "Can't open $ARGS{C_FILE}: $!";
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}
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my $xs_fh = $ARGS{XS_FH};
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if (!$xs_fh) {
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if ($] <= 5.008) {
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require FileHandle;
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$xs_fh = FileHandle->new();
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}
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open $xs_fh, ">$ARGS{XS_FILE}" or die "Can't open $ARGS{XS_FILE}: $!";
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}
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# As this subroutine is intended to make code that isn't edited, there's no
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# need for the user to specify any types that aren't found in the list of
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# names.
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if ($ARGS{PROXYSUBS}) {
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$ARGS{C_FH} = $c_fh;
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$ARGS{XS_FH} = $xs_fh;
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ExtUtils::Constant::ProxySubs->WriteConstants(%ARGS);
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} else {
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my $types = {};
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print $c_fh constant_types(); # macro defs
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print $c_fh "\n";
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# indent is still undef. Until anyone implements indent style rules with
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# it.
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foreach (ExtUtils::Constant::XS->C_constant({package => $ARGS{NAME},
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subname => $ARGS{C_SUBNAME},
|
|
default_type =>
|
|
$ARGS{DEFAULT_TYPE},
|
|
types => $types,
|
|
breakout =>
|
|
$ARGS{BREAKOUT_AT}},
|
|
@{$ARGS{NAMES}})) {
|
|
print $c_fh $_, "\n"; # C constant subs
|
|
}
|
|
print $xs_fh XS_constant ($ARGS{NAME}, $types, $ARGS{XS_SUBNAME},
|
|
$ARGS{C_SUBNAME});
|
|
}
|
|
|
|
close $c_fh or warn "Error closing $ARGS{C_FILE}: $!" unless $ARGS{C_FH};
|
|
close $xs_fh or warn "Error closing $ARGS{XS_FILE}: $!" unless $ARGS{XS_FH};
|
|
}
|
|
|
|
1;
|
|
__END__
|
|
|
|
=back
|
|
|
|
=head1 AUTHOR
|
|
|
|
Nicholas Clark <nick@ccl4.org> based on the code in C<h2xs> by Larry Wall and
|
|
others
|
|
|
|
=cut
|