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1 | package Module::Load::Conditional; |
2 | |
3 | use strict; |
4 | |
5 | use Module::Load; |
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6 | use Params::Check qw[check]; |
7 | use Locale::Maketext::Simple Style => 'gettext'; |
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8 | |
9 | use Carp (); |
10 | use File::Spec (); |
11 | use FileHandle (); |
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12 | use version; |
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13 | |
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14 | use constant ON_VMS => $^O eq 'VMS'; |
15 | |
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16 | BEGIN { |
17 | use vars qw[ $VERSION @ISA $VERBOSE $CACHE @EXPORT_OK |
18 | $FIND_VERSION $ERROR $CHECK_INC_HASH]; |
19 | use Exporter; |
20 | @ISA = qw[Exporter]; |
687d0cf8 |
21 | $VERSION = '0.28_01'; |
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22 | $VERBOSE = 0; |
23 | $FIND_VERSION = 1; |
24 | $CHECK_INC_HASH = 0; |
25 | @EXPORT_OK = qw[check_install can_load requires]; |
26 | } |
27 | |
28 | =pod |
29 | |
30 | =head1 NAME |
31 | |
32 | Module::Load::Conditional - Looking up module information / loading at runtime |
33 | |
34 | =head1 SYNOPSIS |
35 | |
36 | use Module::Load::Conditional qw[can_load check_install requires]; |
37 | |
38 | |
39 | my $use_list = { |
40 | CPANPLUS => 0.05, |
41 | LWP => 5.60, |
42 | 'Test::More' => undef, |
43 | }; |
44 | |
45 | print can_load( modules => $use_list ) |
46 | ? 'all modules loaded successfully' |
47 | : 'failed to load required modules'; |
48 | |
49 | |
50 | my $rv = check_install( module => 'LWP', version => 5.60 ) |
51 | or print 'LWP is not installed!'; |
52 | |
53 | print 'LWP up to date' if $rv->{uptodate}; |
54 | print "LWP version is $rv->{version}\n"; |
55 | print "LWP is installed as file $rv->{file}\n"; |
56 | |
57 | |
58 | print "LWP requires the following modules to be installed:\n"; |
59 | print join "\n", requires('LWP'); |
60 | |
61 | ### allow M::L::C to peek in your %INC rather than just |
62 | ### scanning @INC |
63 | $Module::Load::Conditional::CHECK_INC_HASH = 1; |
64 | |
65 | ### reset the 'can_load' cache |
66 | undef $Module::Load::Conditional::CACHE; |
67 | |
68 | ### don't have Module::Load::Conditional issue warnings -- |
69 | ### default is '1' |
70 | $Module::Load::Conditional::VERBOSE = 0; |
71 | |
72 | ### The last error that happened during a call to 'can_load' |
73 | my $err = $Module::Load::Conditional::ERROR; |
74 | |
75 | |
76 | =head1 DESCRIPTION |
77 | |
78 | Module::Load::Conditional provides simple ways to query and possibly load any of |
79 | the modules you have installed on your system during runtime. |
80 | |
81 | It is able to load multiple modules at once or none at all if one of |
82 | them was not able to load. It also takes care of any error checking |
83 | and so forth. |
84 | |
85 | =head1 Methods |
86 | |
87 | =head1 $href = check_install( module => NAME [, version => VERSION, verbose => BOOL ] ); |
88 | |
89 | C<check_install> allows you to verify if a certain module is installed |
90 | or not. You may call it with the following arguments: |
91 | |
92 | =over 4 |
93 | |
94 | =item module |
95 | |
96 | The name of the module you wish to verify -- this is a required key |
97 | |
98 | =item version |
99 | |
100 | The version this module needs to be -- this is optional |
101 | |
102 | =item verbose |
103 | |
104 | Whether or not to be verbose about what it is doing -- it will default |
105 | to $Module::Load::Conditional::VERBOSE |
106 | |
107 | =back |
108 | |
109 | It will return undef if it was not able to find where the module was |
110 | installed, or a hash reference with the following keys if it was able |
111 | to find the file: |
112 | |
113 | =over 4 |
114 | |
115 | =item file |
116 | |
117 | Full path to the file that contains the module |
118 | |
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119 | =item dir |
120 | |
121 | Directory, or more exact the C<@INC> entry, where the module was |
122 | loaded from. |
123 | |
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124 | =item version |
125 | |
126 | The version number of the installed module - this will be C<undef> if |
127 | the module had no (or unparsable) version number, or if the variable |
128 | C<$Module::Load::Conditional::FIND_VERSION> was set to true. |
129 | (See the C<GLOBAL VARIABLES> section below for details) |
130 | |
131 | =item uptodate |
132 | |
133 | A boolean value indicating whether or not the module was found to be |
134 | at least the version you specified. If you did not specify a version, |
135 | uptodate will always be true if the module was found. |
136 | If no parsable version was found in the module, uptodate will also be |
137 | true, since C<check_install> had no way to verify clearly. |
138 | |
139 | =back |
140 | |
141 | =cut |
142 | |
143 | ### this checks if a certain module is installed already ### |
144 | ### if it returns true, the module in question is already installed |
145 | ### or we found the file, but couldn't open it, OR there was no version |
146 | ### to be found in the module |
147 | ### it will return 0 if the version in the module is LOWER then the one |
148 | ### we are looking for, or if we couldn't find the desired module to begin with |
149 | ### if the installed version is higher or equal to the one we want, it will return |
150 | ### a hashref with he module name and version in it.. so 'true' as well. |
151 | sub check_install { |
152 | my %hash = @_; |
153 | |
154 | my $tmpl = { |
155 | version => { default => '0.0' }, |
156 | module => { required => 1 }, |
157 | verbose => { default => $VERBOSE }, |
158 | }; |
159 | |
160 | my $args; |
161 | unless( $args = check( $tmpl, \%hash, $VERBOSE ) ) { |
162 | warn loc( q[A problem occurred checking arguments] ) if $VERBOSE; |
163 | return; |
164 | } |
165 | |
166 | my $file = File::Spec->catfile( split /::/, $args->{module} ) . '.pm'; |
167 | my $file_inc = File::Spec::Unix->catfile( |
168 | split /::/, $args->{module} |
169 | ) . '.pm'; |
170 | |
171 | ### where we store the return value ### |
172 | my $href = { |
173 | file => undef, |
174 | version => undef, |
175 | uptodate => undef, |
176 | }; |
177 | |
178 | my $filename; |
179 | |
180 | ### check the inc hash if we're allowed to |
181 | if( $CHECK_INC_HASH ) { |
182 | $filename = $href->{'file'} = |
183 | $INC{ $file_inc } if defined $INC{ $file_inc }; |
184 | |
185 | ### find the version by inspecting the package |
186 | if( defined $filename && $FIND_VERSION ) { |
187 | no strict 'refs'; |
188 | $href->{version} = ${ "$args->{module}"."::VERSION" }; |
189 | } |
190 | } |
191 | |
192 | ### we didnt find the filename yet by looking in %INC, |
193 | ### so scan the dirs |
194 | unless( $filename ) { |
195 | |
196 | DIR: for my $dir ( @INC ) { |
197 | |
198 | my $fh; |
199 | |
200 | if ( ref $dir ) { |
201 | ### @INC hook -- we invoke it and get the filehandle back |
202 | ### this is actually documented behaviour as of 5.8 ;) |
203 | |
204 | if (UNIVERSAL::isa($dir, 'CODE')) { |
205 | ($fh) = $dir->($dir, $file); |
206 | |
207 | } elsif (UNIVERSAL::isa($dir, 'ARRAY')) { |
208 | ($fh) = $dir->[0]->($dir, $file, @{$dir}{1..$#{$dir}}) |
209 | |
210 | } elsif (UNIVERSAL::can($dir, 'INC')) { |
211 | ($fh) = $dir->INC->($dir, $file); |
212 | } |
213 | |
214 | if (!UNIVERSAL::isa($fh, 'GLOB')) { |
215 | warn loc(q[Cannot open file '%1': %2], $file, $!) |
216 | if $args->{verbose}; |
217 | next; |
218 | } |
219 | |
220 | $filename = $INC{$file_inc} || $file; |
221 | |
222 | } else { |
223 | $filename = File::Spec->catfile($dir, $file); |
224 | next unless -e $filename; |
225 | |
226 | $fh = new FileHandle; |
227 | if (!$fh->open($filename)) { |
228 | warn loc(q[Cannot open file '%1': %2], $file, $!) |
229 | if $args->{verbose}; |
230 | next; |
231 | } |
232 | } |
233 | |
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234 | ### store the directory we found the file in |
235 | $href->{dir} = $dir; |
236 | |
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237 | ### files need to be in unix format under vms, |
238 | ### or they might be loaded twice |
239 | $href->{file} = ON_VMS |
240 | ? VMS::Filespec::unixify( $filename ) |
241 | : $filename; |
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242 | |
243 | ### user wants us to find the version from files |
244 | if( $FIND_VERSION ) { |
245 | |
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246 | my $in_pod = 0; |
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247 | while ( my $line = <$fh> ) { |
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248 | |
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249 | ### stolen from EU::MM_Unix->parse_version to address |
250 | ### #24062: "Problem with CPANPLUS 0.076 misidentifying |
251 | ### versions after installing Text::NSP 1.03" where a |
252 | ### VERSION mentioned in the POD was found before |
253 | ### the real $VERSION declaration. |
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254 | $in_pod = $line =~ /^=(?!cut)/ ? 1 : |
255 | $line =~ /^=cut/ ? 0 : |
256 | $in_pod; |
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257 | next if $in_pod; |
258 | |
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259 | ### try to find a version declaration in this string. |
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260 | my $ver = __PACKAGE__->_parse_version( $line ); |
91e53322 |
261 | |
262 | if( defined $ver ) { |
263 | $href->{version} = $ver; |
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264 | |
265 | last DIR; |
266 | } |
267 | } |
268 | } |
269 | } |
270 | } |
271 | |
272 | ### if we couldn't find the file, return undef ### |
273 | return unless defined $href->{file}; |
274 | |
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275 | ### only complain if we're expected to find a version higher than 0.0 anyway |
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276 | if( $FIND_VERSION and not defined $href->{version} ) { |
277 | { ### don't warn about the 'not numeric' stuff ### |
278 | local $^W; |
279 | |
280 | ### if we got here, we didn't find the version |
281 | warn loc(q[Could not check version on '%1'], $args->{module} ) |
282 | if $args->{verbose} and $args->{version} > 0; |
283 | } |
284 | $href->{uptodate} = 1; |
285 | |
286 | } else { |
287 | ### don't warn about the 'not numeric' stuff ### |
288 | local $^W; |
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289 | |
290 | ### use qv(), as it will deal with developer release number |
291 | ### ie ones containing _ as well. This addresses bug report |
292 | ### #29348: Version compare logic doesn't handle alphas? |
aacdad3c |
293 | ### |
294 | ### Update from JPeacock: apparently qv() and version->new |
295 | ### are different things, and we *must* use version->new |
296 | ### here, or things like #30056 might start happening |
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297 | $href->{uptodate} = |
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298 | version->new( $args->{version} ) <= version->new( $href->{version} ) |
299 | ? 1 |
300 | : 0; |
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301 | } |
302 | |
303 | return $href; |
304 | } |
305 | |
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306 | sub _parse_version { |
307 | my $self = shift; |
308 | my $str = shift or return; |
309 | my $verbose = shift or 0; |
310 | |
311 | ### skip commented out lines, they won't eval to anything. |
312 | return if $str =~ /^\s*#/; |
313 | |
314 | ### the following regexp & eval statement comes from the |
315 | ### ExtUtils::MakeMaker source (EU::MM_Unix->parse_version) |
316 | ### Following #18892, which tells us the original |
317 | ### regex breaks under -T, we must modifiy it so |
318 | ### it captures the entire expression, and eval /that/ |
319 | ### rather than $_, which is insecure. |
aacdad3c |
320 | my $taint_safe_str = do { $str =~ /(^.*$)/sm; $1 }; |
321 | |
91e53322 |
322 | if( $str =~ /(?<!\\)([\$*])(([\w\:\']*)\bVERSION)\b.*\=/ ) { |
323 | |
324 | print "Evaluating: $str\n" if $verbose; |
325 | |
326 | ### this creates a string to be eval'd, like: |
327 | # package Module::Load::Conditional::_version; |
328 | # no strict; |
329 | # |
330 | # local $VERSION; |
331 | # $VERSION=undef; do { |
332 | # use version; $VERSION = qv('0.0.3'); |
333 | # }; $VERSION |
334 | |
335 | my $eval = qq{ |
336 | package Module::Load::Conditional::_version; |
337 | no strict; |
338 | |
339 | local $1$2; |
340 | \$$2=undef; do { |
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341 | $taint_safe_str |
91e53322 |
342 | }; \$$2 |
343 | }; |
344 | |
345 | print "Evaltext: $eval\n" if $verbose; |
346 | |
347 | my $result = do { |
348 | local $^W = 0; |
349 | eval($eval); |
350 | }; |
351 | |
352 | |
353 | my $rv = defined $result ? $result : '0.0'; |
354 | |
355 | print( $@ ? "Error: $@\n" : "Result: $rv\n" ) if $verbose; |
356 | |
357 | return $rv; |
358 | } |
359 | |
360 | ### unable to find a version in this string |
361 | return; |
362 | } |
363 | |
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364 | =head2 $bool = can_load( modules => { NAME => VERSION [,NAME => VERSION] }, [verbose => BOOL, nocache => BOOL] ) |
365 | |
366 | C<can_load> will take a list of modules, optionally with version |
367 | numbers and determine if it is able to load them. If it can load *ALL* |
368 | of them, it will. If one or more are unloadable, none will be loaded. |
369 | |
370 | This is particularly useful if you have More Than One Way (tm) to |
371 | solve a problem in a program, and only wish to continue down a path |
372 | if all modules could be loaded, and not load them if they couldn't. |
373 | |
374 | This function uses the C<load> function from Module::Load under the |
375 | hood. |
376 | |
377 | C<can_load> takes the following arguments: |
378 | |
379 | =over 4 |
380 | |
381 | =item modules |
382 | |
383 | This is a hashref of module/version pairs. The version indicates the |
384 | minimum version to load. If no version is provided, any version is |
385 | assumed to be good enough. |
386 | |
387 | =item verbose |
388 | |
389 | This controls whether warnings should be printed if a module failed |
390 | to load. |
391 | The default is to use the value of $Module::Load::Conditional::VERBOSE. |
392 | |
393 | =item nocache |
394 | |
395 | C<can_load> keeps its results in a cache, so it will not load the |
396 | same module twice, nor will it attempt to load a module that has |
397 | already failed to load before. By default, C<can_load> will check its |
398 | cache, but you can override that by setting C<nocache> to true. |
399 | |
400 | =cut |
401 | |
402 | sub can_load { |
403 | my %hash = @_; |
404 | |
405 | my $tmpl = { |
406 | modules => { default => {}, strict_type => 1 }, |
407 | verbose => { default => $VERBOSE }, |
408 | nocache => { default => 0 }, |
409 | }; |
410 | |
411 | my $args; |
412 | |
413 | unless( $args = check( $tmpl, \%hash, $VERBOSE ) ) { |
414 | $ERROR = loc(q[Problem validating arguments!]); |
415 | warn $ERROR if $VERBOSE; |
416 | return; |
417 | } |
418 | |
419 | ### layout of $CACHE: |
420 | ### $CACHE = { |
421 | ### $ module => { |
422 | ### usable => BOOL, |
423 | ### version => \d, |
424 | ### file => /path/to/file, |
425 | ### }, |
426 | ### }; |
427 | |
428 | $CACHE ||= {}; # in case it was undef'd |
429 | |
430 | my $error; |
431 | BLOCK: { |
432 | my $href = $args->{modules}; |
433 | |
434 | my @load; |
435 | for my $mod ( keys %$href ) { |
436 | |
437 | next if $CACHE->{$mod}->{usable} && !$args->{nocache}; |
438 | |
439 | ### else, check if the hash key is defined already, |
440 | ### meaning $mod => 0, |
441 | ### indicating UNSUCCESSFUL prior attempt of usage |
3fa779ab |
442 | |
443 | ### use qv(), as it will deal with developer release number |
444 | ### ie ones containing _ as well. This addresses bug report |
445 | ### #29348: Version compare logic doesn't handle alphas? |
aacdad3c |
446 | ### |
447 | ### Update from JPeacock: apparently qv() and version->new |
448 | ### are different things, and we *must* use version->new |
449 | ### here, or things like #30056 might start happening |
0dc418cb |
450 | if ( !$args->{nocache} |
451 | && defined $CACHE->{$mod}->{usable} |
aacdad3c |
452 | && (version->new( $CACHE->{$mod}->{version}||0 ) |
453 | >= version->new( $href->{$mod} ) ) |
0dc418cb |
454 | ) { |
455 | $error = loc( q[Already tried to use '%1', which was unsuccessful], $mod); |
456 | last BLOCK; |
457 | } |
458 | |
459 | my $mod_data = check_install( |
460 | module => $mod, |
461 | version => $href->{$mod} |
462 | ); |
463 | |
464 | if( !$mod_data or !defined $mod_data->{file} ) { |
465 | $error = loc(q[Could not find or check module '%1'], $mod); |
466 | $CACHE->{$mod}->{usable} = 0; |
467 | last BLOCK; |
468 | } |
469 | |
470 | map { |
471 | $CACHE->{$mod}->{$_} = $mod_data->{$_} |
472 | } qw[version file uptodate]; |
473 | |
474 | push @load, $mod; |
475 | } |
476 | |
477 | for my $mod ( @load ) { |
478 | |
479 | if ( $CACHE->{$mod}->{uptodate} ) { |
480 | |
481 | eval { load $mod }; |
482 | |
483 | ### in case anything goes wrong, log the error, the fact |
484 | ### we tried to use this module and return 0; |
485 | if( $@ ) { |
486 | $error = $@; |
487 | $CACHE->{$mod}->{usable} = 0; |
488 | last BLOCK; |
489 | } else { |
490 | $CACHE->{$mod}->{usable} = 1; |
491 | } |
492 | |
493 | ### module not found in @INC, store the result in |
494 | ### $CACHE and return 0 |
495 | } else { |
496 | |
497 | $error = loc(q[Module '%1' is not uptodate!], $mod); |
498 | $CACHE->{$mod}->{usable} = 0; |
499 | last BLOCK; |
500 | } |
501 | } |
502 | |
503 | } # BLOCK |
504 | |
505 | if( defined $error ) { |
506 | $ERROR = $error; |
507 | Carp::carp( loc(q|%1 [THIS MAY BE A PROBLEM!]|,$error) ) if $args->{verbose}; |
3fa779ab |
508 | return; |
0dc418cb |
509 | } else { |
510 | return 1; |
511 | } |
512 | } |
513 | |
3fa779ab |
514 | =back |
515 | |
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516 | =head2 @list = requires( MODULE ); |
517 | |
518 | C<requires> can tell you what other modules a particular module |
519 | requires. This is particularly useful when you're intending to write |
520 | a module for public release and are listing its prerequisites. |
521 | |
522 | C<requires> takes but one argument: the name of a module. |
523 | It will then first check if it can actually load this module, and |
524 | return undef if it can't. |
525 | Otherwise, it will return a list of modules and pragmas that would |
526 | have been loaded on the module's behalf. |
527 | |
528 | Note: The list C<require> returns has originated from your current |
529 | perl and your current install. |
530 | |
531 | =cut |
532 | |
533 | sub requires { |
534 | my $who = shift; |
535 | |
536 | unless( check_install( module => $who ) ) { |
537 | warn loc(q[You do not have module '%1' installed], $who) if $VERBOSE; |
538 | return undef; |
539 | } |
540 | |
541 | my $lib = join " ", map { qq["-I$_"] } @INC; |
542 | my $cmd = qq[$^X $lib -M$who -e"print(join(qq[\\n],keys(%INC)))"]; |
543 | |
544 | return sort |
545 | grep { !/^$who$/ } |
546 | map { chomp; s|/|::|g; $_ } |
547 | grep { s|\.pm$||i; } |
548 | `$cmd`; |
549 | } |
550 | |
551 | 1; |
552 | |
553 | __END__ |
554 | |
555 | =head1 Global Variables |
556 | |
557 | The behaviour of Module::Load::Conditional can be altered by changing the |
558 | following global variables: |
559 | |
560 | =head2 $Module::Load::Conditional::VERBOSE |
561 | |
562 | This controls whether Module::Load::Conditional will issue warnings and |
563 | explanations as to why certain things may have failed. If you set it |
564 | to 0, Module::Load::Conditional will not output any warnings. |
565 | The default is 0; |
566 | |
567 | =head2 $Module::Load::Conditional::FIND_VERSION |
568 | |
569 | This controls whether Module::Load::Conditional will try to parse |
570 | (and eval) the version from the module you're trying to load. |
571 | |
572 | If you don't wish to do this, set this variable to C<false>. Understand |
573 | then that version comparisons are not possible, and Module::Load::Conditional |
574 | can not tell you what module version you have installed. |
575 | This may be desirable from a security or performance point of view. |
576 | Note that C<$FIND_VERSION> code runs safely under C<taint mode>. |
577 | |
578 | The default is 1; |
579 | |
580 | =head2 $Module::Load::Conditional::CHECK_INC_HASH |
581 | |
582 | This controls whether C<Module::Load::Conditional> checks your |
583 | C<%INC> hash to see if a module is available. By default, only |
584 | C<@INC> is scanned to see if a module is physically on your |
585 | filesystem, or avialable via an C<@INC-hook>. Setting this variable |
586 | to C<true> will trust any entries in C<%INC> and return them for |
587 | you. |
588 | |
589 | The default is 0; |
590 | |
591 | =head2 $Module::Load::Conditional::CACHE |
592 | |
593 | This holds the cache of the C<can_load> function. If you explicitly |
594 | want to remove the current cache, you can set this variable to |
595 | C<undef> |
596 | |
597 | =head2 $Module::Load::Conditional::ERROR |
598 | |
599 | This holds a string of the last error that happened during a call to |
600 | C<can_load>. It is useful to inspect this when C<can_load> returns |
601 | C<undef>. |
602 | |
603 | =head1 See Also |
604 | |
605 | C<Module::Load> |
606 | |
3fa779ab |
607 | =head1 BUG REPORTS |
608 | |
609 | Please report bugs or other issues to E<lt>bug-module-load-conditional@rt.cpan.orgE<gt>. |
610 | |
0dc418cb |
611 | =head1 AUTHOR |
612 | |
3fa779ab |
613 | This module by Jos Boumans E<lt>kane@cpan.orgE<gt>. |
0dc418cb |
614 | |
615 | =head1 COPYRIGHT |
616 | |
3fa779ab |
617 | This library is free software; you may redistribute and/or modify it |
618 | under the same terms as Perl itself. |
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619 | |
3fa779ab |
620 | =cut |