See also the documentation of C<use VERSION> and C<require VERSION>
for a convenient way to fail if the Perl interpreter is too old.
+=item $COMPILING
+
+=item $^C
+
+The current value of the flag associated with the B<-c> switch. Mainly
+of use with B<-MO=...> to allow code to alter its behaviour when being compiled.
+(For example to automatically AUTOLOADing at compile time rather than normal
+deferred loading.) Setting C<$^C = 1> is similar to calling C<B::minus_c>.
+
=item $DEBUGGING
=item $^D
The C<require> command uses this array to determine whether a given file
has already been included.
-=item %ENV $ENV{expr}
+=item %ENV
+
+=item $ENV{expr}
The hash %ENV contains your current environment. Setting a
value in C<ENV> changes the environment for child processes.
-=item %SIG $SIG{expr}
+=item %SIG
+
+=item $SIG{expr}
The hash %SIG is used to set signal handlers for various
signals. Example: