Note that formats are treated as anon subs, and are cloned each time
write is called (if necessary).
-The flag SVf_PADSTALE is cleared on lexicals each time the my() is executed,
+The flag SVs_PADSTALE is cleared on lexicals each time the my() is executed,
and set on scope exit. This allows the 'Variable $x is not available' warning
to be generated in evals, such as
{ my $x = 1; sub f { eval '$x'} } f();
-For state vars, SVf_PADSTALE is overloaded to mean 'not yet initialised'
+For state vars, SVs_PADSTALE is overloaded to mean 'not yet initialised'
=cut
*/