--- AnyEvent/lib/AnyEvent.pm	2008/05/10 00:45:18	1.109
+++ AnyEvent/lib/AnyEvent.pm	2008/05/10 00:57:31	1.110
@@ -551,11 +551,14 @@
 have created an AnyEvent watcher anyway, that is, as late as possible at
 runtime.
 
-=item AnyEvent::on_detect { BLOCK }
+=item $guard = AnyEvent::on_detect { BLOCK }
 
 Arranges for the code block to be executed as soon as the event model is
 autodetected (or immediately if this has already happened).
 
+If called in scalar or list context, then it creates and returns an object
+that automatically removes the callback again when it is destroyed.
+
 =item @AnyEvent::on_detect
 
 If there are any code references in this array (you can C<push> to it
@@ -721,13 +724,25 @@
 our @on_detect;
 
 sub on_detect(&) {
+   my ($cb) = @_;
+
    if ($MODEL) {
-      $_[0]->();
+      $cb->();
+
+      1
    } else {
-      push @on_detect, $_[0];
+      push @on_detect, $cb;
+
+      defined wantarray
+         ? bless \$cb, "AnyEvent::Util::Guard"
+         : ()
    }
 }
 
+sub AnyEvent::Util::Guard::DESTROY {
+   @on_detect = grep $_ != ${$_[0]}, @on_detect;
+}
+
 sub detect() {
    unless ($MODEL) {
       no strict 'refs';