perl reference counting of objects works fine, no dangers of double-d…

…estruction

git-svn-id: svn://localhost/Crypt-GCrypt/trunk@82 c2f821fb-fd85-dc11-8383-000bcdcb7a8f

lib/Crypt/GCrypt/MPI.pm

@@ -98,12 +98,11 @@ greater, negative if $other is greater.
 =head2 copy()
 
 Returns a new Crypt::GCrypt::MPI object, with the contents identical
-to this one.  This is better than using the assignment operator (=).
-For example:
+to this one.  This is different from using the assignment operator
+(=), which just makes two references to the same object.  For example:
 
  $b = new Crypt::GCrypt::MPI(15);
- $a = $b; # DANGER! this may cause a double-free
-          # when $a and $b fall out of scope.
+ $a = $b;
  $b->add(1); # $a points to the same object,
              # so both $a and $b contain 16.
 

t/20-mpi.t

@@ -107,3 +107,10 @@ $y->sub($thirtysix);
 ok(0 == $y->cmp(Crypt::GCrypt::MPI->new(65501)));
 ok(0 == $x->cmp(Crypt::GCrypt::MPI->new(65537)));
 
+{ my $a = $y;
+ $a->sub($thirtysix);
+};
+
+$y->sub($thirtysix);
+
+ok(0 == $y->cmp(Crypt::GCrypt::MPI->new(65429)));