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1 | package ExtUtils::Constant; |
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2 | use vars qw (@ISA $VERSION @EXPORT_OK %EXPORT_TAGS); |
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3 | $VERSION = 0.17; |
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4 | |
5 | =head1 NAME |
6 | |
7 | ExtUtils::Constant - generate XS code to import C header constants |
8 | |
9 | =head1 SYNOPSIS |
10 | |
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11 | use ExtUtils::Constant qw (WriteConstants); |
12 | WriteConstants( |
13 | NAME => 'Foo', |
14 | NAMES => [qw(FOO BAR BAZ)], |
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15 | ); |
16 | # Generates wrapper code to make the values of the constants FOO BAR BAZ |
17 | # available to perl |
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18 | |
19 | =head1 DESCRIPTION |
20 | |
21 | ExtUtils::Constant facilitates generating C and XS wrapper code to allow |
22 | perl modules to AUTOLOAD constants defined in C library header files. |
23 | It is principally used by the C<h2xs> utility, on which this code is based. |
24 | It doesn't contain the routines to scan header files to extract these |
25 | constants. |
26 | |
27 | =head1 USAGE |
28 | |
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29 | Generally one only needs to call the C<WriteConstants> function, and then |
30 | |
1cb0fb50 |
31 | #include "const-c.inc" |
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32 | |
33 | in the C section of C<Foo.xs> |
34 | |
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35 | INCLUDE: const-xs.inc |
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36 | |
37 | in the XS section of C<Foo.xs>. |
38 | |
39 | For greater flexibility use C<constant_types()>, C<C_constant> and |
40 | C<XS_constant>, with which C<WriteConstants> is implemented. |
af6c647e |
41 | |
42 | Currently this module understands the following types. h2xs may only know |
43 | a subset. The sizes of the numeric types are chosen by the C<Configure> |
44 | script at compile time. |
45 | |
46 | =over 4 |
47 | |
48 | =item IV |
49 | |
50 | signed integer, at least 32 bits. |
51 | |
52 | =item UV |
53 | |
54 | unsigned integer, the same size as I<IV> |
55 | |
56 | =item NV |
57 | |
58 | floating point type, probably C<double>, possibly C<long double> |
59 | |
60 | =item PV |
61 | |
62 | NUL terminated string, length will be determined with C<strlen> |
63 | |
64 | =item PVN |
65 | |
66 | A fixed length thing, given as a [pointer, length] pair. If you know the |
67 | length of a string at compile time you may use this instead of I<PV> |
68 | |
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69 | =item SV |
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70 | |
71 | A B<mortal> SV. |
72 | |
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73 | =item YES |
74 | |
75 | Truth. (C<PL_sv_yes>) The value is not needed (and ignored). |
76 | |
77 | =item NO |
78 | |
79 | Defined Falsehood. (C<PL_sv_no>) The value is not needed (and ignored). |
80 | |
81 | =item UNDEF |
82 | |
83 | C<undef>. The value of the macro is not needed. |
84 | |
af6c647e |
85 | =back |
86 | |
87 | =head1 FUNCTIONS |
88 | |
89 | =over 4 |
90 | |
91 | =cut |
92 | |
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93 | if ($] >= 5.006) { |
94 | eval "use warnings; 1" or die $@; |
95 | } |
af6c647e |
96 | use strict; |
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97 | use Carp qw(croak cluck); |
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98 | |
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99 | use Exporter; |
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100 | use ExtUtils::Constant::Utils qw(C_stringify); |
101 | use ExtUtils::Constant::XS qw(%XS_Constant %XS_TypeSet); |
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102 | |
103 | @ISA = 'Exporter'; |
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104 | |
105 | %EXPORT_TAGS = ( 'all' => [ qw( |
106 | XS_constant constant_types return_clause memEQ_clause C_stringify |
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107 | C_constant autoload WriteConstants WriteMakefileSnippet |
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108 | ) ] ); |
109 | |
110 | @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } ); |
111 | |
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112 | =item constant_types |
113 | |
114 | A function returning a single scalar with C<#define> definitions for the |
115 | constants used internally between the generated C and XS functions. |
116 | |
117 | =cut |
118 | |
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119 | sub constant_types { |
120 | ExtUtils::Constant::XS->header(); |
af6c647e |
121 | } |
122 | |
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123 | sub memEQ_clause { |
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124 | cluck "ExtUtils::Constant::memEQ_clause is deprecated"; |
125 | ExtUtils::Constant::XS->memEQ_clause({name=>$_[0], checked_at=>$_[1], |
126 | indent=>$_[2]}); |
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127 | } |
128 | |
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129 | sub return_clause ($$) { |
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130 | cluck "ExtUtils::Constant::return_clause is deprecated"; |
131 | my $indent = shift; |
132 | ExtUtils::Constant::XS->return_clause({indent=>$indent}, @_); |
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133 | } |
134 | |
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135 | sub switch_clause { |
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136 | cluck "ExtUtils::Constant::switch_clause is deprecated"; |
137 | my $indent = shift; |
138 | my $comment = shift; |
139 | ExtUtils::Constant::XS->switch_clause({indent=>$indent, comment=>$comment}, |
140 | @_); |
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141 | } |
142 | |
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143 | sub C_constant { |
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144 | my ($package, $subname, $default_type, $what, $indent, $breakout, @items) |
145 | = @_; |
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146 | ExtUtils::Constant::XS->C_constant({package => $package, subname => $subname, |
147 | default_type => $default_type, |
148 | types => $what, indent => $indent, |
149 | breakout => $breakout}, @items); |
af6c647e |
150 | } |
151 | |
152 | =item XS_constant PACKAGE, TYPES, SUBNAME, C_SUBNAME |
153 | |
154 | A function to generate the XS code to implement the perl subroutine |
155 | I<PACKAGE>::constant used by I<PACKAGE>::AUTOLOAD to load constants. |
156 | This XS code is a wrapper around a C subroutine usually generated by |
157 | C<C_constant>, and usually named C<constant>. |
158 | |
159 | I<TYPES> should be given either as a comma separated list of types that the |
160 | C subroutine C<constant> will generate or as a reference to a hash. It should |
161 | be the same list of types as C<C_constant> was given. |
162 | [Otherwise C<XS_constant> and C<C_constant> may have different ideas about |
163 | the number of parameters passed to the C function C<constant>] |
164 | |
165 | You can call the perl visible subroutine something other than C<constant> if |
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166 | you give the parameter I<SUBNAME>. The C subroutine it calls defaults to |
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167 | the name of the perl visible subroutine, unless you give the parameter |
168 | I<C_SUBNAME>. |
169 | |
170 | =cut |
171 | |
172 | sub XS_constant { |
173 | my $package = shift; |
174 | my $what = shift; |
175 | my $subname = shift; |
176 | my $C_subname = shift; |
177 | $subname ||= 'constant'; |
178 | $C_subname ||= $subname; |
179 | |
180 | if (!ref $what) { |
181 | # Convert line of the form IV,UV,NV to hash |
182 | $what = {map {$_ => 1} split /,\s*/, ($what)}; |
183 | } |
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184 | my $params = ExtUtils::Constant::XS->params ($what); |
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185 | my $type; |
186 | |
187 | my $xs = <<"EOT"; |
188 | void |
189 | $subname(sv) |
190 | PREINIT: |
191 | #ifdef dXSTARG |
192 | dXSTARG; /* Faster if we have it. */ |
193 | #else |
194 | dTARGET; |
195 | #endif |
196 | STRLEN len; |
197 | int type; |
198 | EOT |
199 | |
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200 | if ($params->{IV}) { |
af6c647e |
201 | $xs .= " IV iv;\n"; |
202 | } else { |
203 | $xs .= " /* IV\t\tiv;\tUncomment this if you need to return IVs */\n"; |
204 | } |
72f7b9a1 |
205 | if ($params->{NV}) { |
af6c647e |
206 | $xs .= " NV nv;\n"; |
207 | } else { |
208 | $xs .= " /* NV\t\tnv;\tUncomment this if you need to return NVs */\n"; |
209 | } |
72f7b9a1 |
210 | if ($params->{PV}) { |
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211 | $xs .= " const char *pv;\n"; |
212 | } else { |
213 | $xs .= |
214 | " /* const char\t*pv;\tUncomment this if you need to return PVs */\n"; |
215 | } |
216 | |
217 | $xs .= << 'EOT'; |
218 | INPUT: |
219 | SV * sv; |
220 | const char * s = SvPV(sv, len); |
6557ab03 |
221 | EOT |
222 | if ($params->{''}) { |
223 | $xs .= << 'EOT'; |
224 | INPUT: |
225 | int utf8 = SvUTF8(sv); |
226 | EOT |
227 | } |
228 | $xs .= << 'EOT'; |
af6c647e |
229 | PPCODE: |
230 | EOT |
231 | |
72f7b9a1 |
232 | if ($params->{IV} xor $params->{NV}) { |
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233 | $xs .= << "EOT"; |
a2c454fa |
234 | /* Change this to $C_subname(aTHX_ s, len, &iv, &nv); |
af6c647e |
235 | if you need to return both NVs and IVs */ |
236 | EOT |
237 | } |
a2c454fa |
238 | $xs .= " type = $C_subname(aTHX_ s, len"; |
6557ab03 |
239 | $xs .= ', utf8' if $params->{''}; |
72f7b9a1 |
240 | $xs .= ', &iv' if $params->{IV}; |
241 | $xs .= ', &nv' if $params->{NV}; |
242 | $xs .= ', &pv' if $params->{PV}; |
243 | $xs .= ', &sv' if $params->{SV}; |
af6c647e |
244 | $xs .= ");\n"; |
245 | |
246 | $xs .= << "EOT"; |
247 | /* Return 1 or 2 items. First is error message, or undef if no error. |
248 | Second, if present, is found value */ |
249 | switch (type) { |
250 | case PERL_constant_NOTFOUND: |
251 | sv = sv_2mortal(newSVpvf("%s is not a valid $package macro", s)); |
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252 | PUSHs(sv); |
af6c647e |
253 | break; |
254 | case PERL_constant_NOTDEF: |
255 | sv = sv_2mortal(newSVpvf( |
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256 | "Your vendor has not defined $package macro %s, used", s)); |
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257 | PUSHs(sv); |
af6c647e |
258 | break; |
259 | EOT |
260 | |
261 | foreach $type (sort keys %XS_Constant) { |
6557ab03 |
262 | # '' marks utf8 flag needed. |
263 | next if $type eq ''; |
af6c647e |
264 | $xs .= "\t/* Uncomment this if you need to return ${type}s\n" |
265 | unless $what->{$type}; |
8ac27563 |
266 | $xs .= " case PERL_constant_IS$type:\n"; |
267 | if (length $XS_Constant{$type}) { |
268 | $xs .= << "EOT"; |
af6c647e |
269 | EXTEND(SP, 1); |
270 | PUSHs(&PL_sv_undef); |
271 | $XS_Constant{$type}; |
af6c647e |
272 | EOT |
8ac27563 |
273 | } else { |
274 | # Do nothing. return (), which will be correctly interpreted as |
275 | # (undef, undef) |
276 | } |
277 | $xs .= " break;\n"; |
af6c647e |
278 | unless ($what->{$type}) { |
279 | chop $xs; # Yes, another need for chop not chomp. |
280 | $xs .= " */\n"; |
281 | } |
282 | } |
283 | $xs .= << "EOT"; |
284 | default: |
285 | sv = sv_2mortal(newSVpvf( |
8ac27563 |
286 | "Unexpected return type %d while processing $package macro %s, used", |
af6c647e |
287 | type, s)); |
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288 | PUSHs(sv); |
af6c647e |
289 | } |
290 | EOT |
291 | |
292 | return $xs; |
293 | } |
294 | |
295 | |
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296 | =item autoload PACKAGE, VERSION, AUTOLOADER |
af6c647e |
297 | |
298 | A function to generate the AUTOLOAD subroutine for the module I<PACKAGE> |
299 | I<VERSION> is the perl version the code should be backwards compatible with. |
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300 | It defaults to the version of perl running the subroutine. If I<AUTOLOADER> |
301 | is true, the AUTOLOAD subroutine falls back on AutoLoader::AUTOLOAD for all |
302 | names that the constant() routine doesn't recognise. |
af6c647e |
303 | |
304 | =cut |
305 | |
6d79cad2 |
306 | # ' # Grr. syntax highlighters that don't grok pod. |
307 | |
af6c647e |
308 | sub autoload { |
6d79cad2 |
309 | my ($module, $compat_version, $autoloader) = @_; |
af6c647e |
310 | $compat_version ||= $]; |
311 | croak "Can't maintain compatibility back as far as version $compat_version" |
312 | if $compat_version < 5; |
6d79cad2 |
313 | my $func = "sub AUTOLOAD {\n" |
314 | . " # This AUTOLOAD is used to 'autoload' constants from the constant()\n" |
315 | . " # XS function."; |
316 | $func .= " If a constant is not found then control is passed\n" |
317 | . " # to the AUTOLOAD in AutoLoader." if $autoloader; |
318 | |
319 | |
320 | $func .= "\n\n" |
321 | . " my \$constname;\n"; |
a2c454fa |
322 | $func .= |
6d79cad2 |
323 | " our \$AUTOLOAD;\n" if ($compat_version >= 5.006); |
324 | |
325 | $func .= <<"EOT"; |
af6c647e |
326 | (\$constname = \$AUTOLOAD) =~ s/.*:://; |
327 | croak "&${module}::constant not defined" if \$constname eq 'constant'; |
328 | my (\$error, \$val) = constant(\$constname); |
6d79cad2 |
329 | EOT |
330 | |
331 | if ($autoloader) { |
332 | $func .= <<'EOT'; |
333 | if ($error) { |
334 | if ($error =~ /is not a valid/) { |
335 | $AutoLoader::AUTOLOAD = $AUTOLOAD; |
af6c647e |
336 | goto &AutoLoader::AUTOLOAD; |
337 | } else { |
6d79cad2 |
338 | croak $error; |
af6c647e |
339 | } |
340 | } |
6d79cad2 |
341 | EOT |
342 | } else { |
343 | $func .= |
344 | " if (\$error) { croak \$error; }\n"; |
345 | } |
346 | |
347 | $func .= <<'END'; |
af6c647e |
348 | { |
349 | no strict 'refs'; |
350 | # Fixed between 5.005_53 and 5.005_61 |
6d79cad2 |
351 | #XXX if ($] >= 5.00561) { |
352 | #XXX *$AUTOLOAD = sub () { $val }; |
af6c647e |
353 | #XXX } |
354 | #XXX else { |
6d79cad2 |
355 | *$AUTOLOAD = sub { $val }; |
af6c647e |
356 | #XXX } |
357 | } |
6d79cad2 |
358 | goto &$AUTOLOAD; |
af6c647e |
359 | } |
360 | |
361 | END |
362 | |
6d79cad2 |
363 | return $func; |
af6c647e |
364 | } |
0552bf3a |
365 | |
366 | |
9a7df4f2 |
367 | =item WriteMakefileSnippet |
368 | |
369 | WriteMakefileSnippet ATTRIBUTE =E<gt> VALUE [, ...] |
370 | |
d1be9408 |
371 | A function to generate perl code for Makefile.PL that will regenerate |
9a7df4f2 |
372 | the constant subroutines. Parameters are named as passed to C<WriteConstants>, |
373 | with the addition of C<INDENT> to specify the number of leading spaces |
374 | (default 2). |
375 | |
376 | Currently only C<INDENT>, C<NAME>, C<DEFAULT_TYPE>, C<NAMES>, C<C_FILE> and |
377 | C<XS_FILE> are recognised. |
378 | |
379 | =cut |
380 | |
381 | sub WriteMakefileSnippet { |
382 | my %args = @_; |
383 | my $indent = $args{INDENT} || 2; |
384 | |
385 | my $result = <<"EOT"; |
386 | ExtUtils::Constant::WriteConstants( |
387 | NAME => '$args{NAME}', |
388 | NAMES => \\\@names, |
389 | DEFAULT_TYPE => '$args{DEFAULT_TYPE}', |
390 | EOT |
391 | foreach (qw (C_FILE XS_FILE)) { |
392 | next unless exists $args{$_}; |
393 | $result .= sprintf " %-12s => '%s',\n", |
394 | $_, $args{$_}; |
395 | } |
396 | $result .= <<'EOT'; |
397 | ); |
398 | EOT |
399 | |
400 | $result =~ s/^/' 'x$indent/gem; |
af6ca1d0 |
401 | return ExtUtils::Constant::XS->dump_names({default_type=>$args{DEFAULT_TYPE}, |
402 | indent=>$indent,}, |
403 | @{$args{NAMES}}) |
404 | . $result; |
9a7df4f2 |
405 | } |
406 | |
0552bf3a |
407 | =item WriteConstants ATTRIBUTE =E<gt> VALUE [, ...] |
408 | |
409 | Writes a file of C code and a file of XS code which you should C<#include> |
410 | and C<INCLUDE> in the C and XS sections respectively of your module's XS |
4f2c4fd8 |
411 | code. You probably want to do this in your C<Makefile.PL>, so that you can |
0552bf3a |
412 | easily edit the list of constants without touching the rest of your module. |
413 | The attributes supported are |
414 | |
415 | =over 4 |
416 | |
417 | =item NAME |
418 | |
419 | Name of the module. This must be specified |
420 | |
421 | =item DEFAULT_TYPE |
422 | |
423 | The default type for the constants. If not specified C<IV> is assumed. |
424 | |
425 | =item BREAKOUT_AT |
426 | |
427 | The names of the constants are grouped by length. Generate child subroutines |
428 | for each group with this number or more names in. |
429 | |
430 | =item NAMES |
431 | |
432 | An array of constants' names, either scalars containing names, or hashrefs |
433 | as detailed in L<"C_constant">. |
434 | |
435 | =item C_FILE |
436 | |
437 | The name of the file to write containing the C code. The default is |
1cb0fb50 |
438 | C<const-c.inc>. The C<-> in the name ensures that the file can't be |
439 | mistaken for anything related to a legitimate perl package name, and |
440 | not naming the file C<.c> avoids having to override Makefile.PL's |
441 | C<.xs> to C<.c> rules. |
0552bf3a |
442 | |
443 | =item XS_FILE |
444 | |
445 | The name of the file to write containing the XS code. The default is |
1cb0fb50 |
446 | C<const-xs.inc>. |
0552bf3a |
447 | |
448 | =item SUBNAME |
449 | |
450 | The perl visible name of the XS subroutine generated which will return the |
9a7df4f2 |
451 | constants. The default is C<constant>. |
0552bf3a |
452 | |
453 | =item C_SUBNAME |
454 | |
455 | The name of the C subroutine generated which will return the constants. |
456 | The default is I<SUBNAME>. Child subroutines have C<_> and the name |
457 | length appended, so constants with 10 character names would be in |
458 | C<constant_10> with the default I<XS_SUBNAME>. |
459 | |
460 | =back |
461 | |
462 | =cut |
463 | |
464 | sub WriteConstants { |
465 | my %ARGS = |
466 | ( # defaults |
1cb0fb50 |
467 | C_FILE => 'const-c.inc', |
468 | XS_FILE => 'const-xs.inc', |
0552bf3a |
469 | SUBNAME => 'constant', |
470 | DEFAULT_TYPE => 'IV', |
471 | @_); |
472 | |
473 | $ARGS{C_SUBNAME} ||= $ARGS{SUBNAME}; # No-one sane will have C_SUBNAME eq '0' |
474 | |
475 | croak "Module name not specified" unless length $ARGS{NAME}; |
476 | |
67a202d9 |
477 | my ($c_fh, $xs_fh); |
478 | if ($] <= 5.008) { |
479 | # We need these little games, rather than doing things unconditionally, |
480 | # because we're used in core Makefile.PLs before IO is available (needed |
481 | # by filehandle), but also we want to work on older perls where undefined |
482 | # scalars do not automatically turn into anonymous file handles. |
483 | require FileHandle; |
484 | $c_fh = FileHandle->new(); |
485 | $xs_fh = FileHandle->new(); |
486 | } |
487 | open $c_fh, ">$ARGS{C_FILE}" or die "Can't open $ARGS{C_FILE}: $!"; |
488 | open $xs_fh, ">$ARGS{XS_FILE}" or die "Can't open $ARGS{XS_FILE}: $!"; |
0552bf3a |
489 | |
490 | # As this subroutine is intended to make code that isn't edited, there's no |
491 | # need for the user to specify any types that aren't found in the list of |
492 | # names. |
493 | my $types = {}; |
494 | |
495 | print $c_fh constant_types(); # macro defs |
496 | print $c_fh "\n"; |
497 | |
4f2c4fd8 |
498 | # indent is still undef. Until anyone implements indent style rules with it. |
af6ca1d0 |
499 | foreach (ExtUtils::Constant::XS->C_constant({package => $ARGS{NAME}, |
500 | subname => $ARGS{C_SUBNAME}, |
501 | default_type => |
502 | $ARGS{DEFAULT_TYPE}, |
503 | types => $types, |
504 | breakout => $ARGS{BREAKOUT_AT}}, |
505 | @{$ARGS{NAMES}})) { |
0552bf3a |
506 | print $c_fh $_, "\n"; # C constant subs |
507 | } |
508 | print $xs_fh XS_constant ($ARGS{NAME}, $types, $ARGS{XS_SUBNAME}, |
509 | $ARGS{C_SUBNAME}); |
510 | |
511 | close $c_fh or warn "Error closing $ARGS{C_FILE}: $!"; |
512 | close $xs_fh or warn "Error closing $ARGS{XS_FILE}: $!"; |
513 | } |
514 | |
af6c647e |
515 | 1; |
516 | __END__ |
517 | |
518 | =back |
519 | |
520 | =head1 AUTHOR |
521 | |
522 | Nicholas Clark <nick@ccl4.org> based on the code in C<h2xs> by Larry Wall and |
523 | others |
524 | |
525 | =cut |