perlfaq7: How can I catch accesses to undefined variables/functions/methods?

* Brian McCauley suggested that this answer use warnings instead of black magic


Index: perlfaq7.pod
===================================================================
RCS file: /cvs/public/perlfaq/perlfaq7.pod,v
retrieving revision 1.10
diff -u -d -r1.10 perlfaq7.pod
--- perlfaq7.pod        4 Sep 2002 22:33:45 -0000       1.10
+++ perlfaq7.pod        5 Nov 2002 02:16:45 -0000
@@ -675,31 +675,16 @@
         print "No such command: $string\n";
     } 
 
-=head2 How can I catch accesses to undefined variables/functions/methods?
+=head2 How can I catch accesses to undefined variables, functions, or methods?
 
 The AUTOLOAD method, discussed in L<perlsub/"Autoloading"> and
 L<perltoot/"AUTOLOAD: Proxy Methods">, lets you capture calls to
 undefined functions and methods.
 
 When it comes to undefined variables that would trigger a warning
-under C<-w>, you can use a handler to trap the pseudo-signal
-C<__WARN__> like this:
-
-    $SIG{__WARN__} = sub {
-
-       for ( $_[0] ) {         # voici un switch statement 
-
-           /Use of uninitialized value/  && do {
-               # promote warning to a fatal
-               die $_;
-           };
-
-           # other warning cases to catch could go here;
-
-           warn $_;
-       }
+under C<use warnings>, you can promote the warning to an error.
 
-    };
+       use warnings FATAL => qw(uninitialized);
 
 =head2 Why can't a method included in this same file be found?