UCD 5.1.0

[p5sagit/p5-mst-13.2.git] / pod / perlobj.pod

diff --git a/pod/perlobj.pod b/pod/perlobj.pod
index bcf56a7..b6638e8 100644 (file)
--- a/pod/perlobj.pod
+++ b/pod/perlobj.pod
@@ -151,8 +151,9 @@ There is a special array within each package called @ISA, which says
 where else to look for a method if you can't find it in the current
 package.  This is how Perl implements inheritance.  Each element of the
 @ISA array is just the name of another package that happens to be a
-class package.  The classes are searched (depth first) for missing
-methods in the order that they occur in @ISA.  The classes accessible
+class package.  The classes are searched for missing methods in
+depth-first, left-to-right order by default (see L<mro> for alternative
+search order and other in-depth information).  The classes accessible
 through @ISA are known as base classes of the current class.
 
 All classes implicitly inherit from class C<UNIVERSAL> as their
@@ -456,6 +457,11 @@ manipulating C<$_[0]> within the destructor.  The object itself (i.e.
 the thingy the reference points to, namely C<${$_[0]}>, C<@{$_[0]}>, 
 C<%{$_[0]}> etc.) is not similarly constrained.
 
+Since DESTROY methods can be called at unpredictable times, it is
+important that you localise any global variables that the method may
+update.  In particular, localise C<$@> if you use C<eval {}> and
+localise C<$?> if you use C<system> or backticks.
+
 If you arrange to re-bless the reference before the destructor returns,
 perl will again call the DESTROY method for the re-blessed object after
 the current one returns.  This can be used for clean delegation of