Re: [REPATCH] Re: [PATCH] Re: [ID 20011030.064] File::Temp tempdir(CLEANUP => 1)...

[perl5.git] / lib / UNIVERSAL.pm

diff --git a/lib/UNIVERSAL.pm b/lib/UNIVERSAL.pm
index f2f1fe9..a9cb478 100644 (file)
--- a/lib/UNIVERSAL.pm
+++ b/lib/UNIVERSAL.pm
@@ -1,5 +1,7 @@
 package UNIVERSAL;
 
+our $VERSION = '1.00';
+
 # UNIVERSAL should not contain any extra subs/methods beyond those
 # that it exists to define. The use of Exporter below is a historical
 # accident that should be fixed sometime.
@@ -43,6 +45,15 @@ C<can> checks if the object has a method called C<METHOD>. If it does
 then a reference to the sub is returned. If it does not then I<undef>
 is returned.
 
+C<can> cannot know whether an object will be able to provide a method
+through AUTOLOAD, so a return value of I<undef> does not necessarily mean
+the object will not be able to handle the method call. To get around
+this some module authors use a forward declaration (see L<perlsub>)
+for methods they will handle via AUTOLOAD. For such 'dummy' subs, C<can>
+will still return a code reference, which, when called, will fall through
+to the AUTOLOAD. If no suitable AUTOLOAD is provided, calling the coderef
+will cause an error.
+
 C<can> can be called as either a static or object method call.
 
 =item VERSION ( [ REQUIRE ] )