$Config{ivsize}. For portability, be sure to mask off the excess bits
in the result of unary C<~>, e.g., C<~$x & 0xffffffff>.
+=head2 The passwd and shell returned by the getpwxxx() are now tainted
+
+Because the user can affect her own encrypted password and login shell
+the password and shell returned by the getpwent(), getpwnam(), and
+getpwuid() functions are tainted.
+
+=head2 The msgrcv() and shmread() now taint
+
+Because other (untrusted) processes can modify messages and shared
+memory segments for their own nefarious purposes, the messages
+returned by msgrcv() (and its object-oriented interface,
+IPC::SysV::Msg::rcv) and the variable modified by shmread() are tainted.
+
=back
=head2 C Source Incompatibilities