perlpragma.pod: Clarify that runtime %^H is ro

You can use (caller(0))[10} to retrieve the contents of %^H, and any
changes you make to your local copy will be lost, but that may not be
immediately apparent to the pod reader.

diff --git a/pod/perlpragma.pod b/pod/perlpragma.pod
index 51292a8..8560144 100644 (file)
--- a/pod/perlpragma.pod
+++ b/pod/perlpragma.pod
@@ -117,8 +117,8 @@ for the user's code.
 
 User pragmata store their state by writing to the magical hash C<%^H>,
 hence these two routines manipulate it. The state information in C<%^H> is
-stored in the optree, and can be retrieved at runtime with C<caller()>, at
-index 10 of the list of returned results. In the example pragma, retrieval
+stored in the optree, and can be retrieved read-only at runtime with C<caller()>,
+at index 10 of the list of returned results. In the example pragma, retrieval
 is encapsulated into the routine C<in_effect()>, which takes as parameter
 the number of call frames to go up to find the value of the pragma in the
 user's script. This uses C<caller()> to determine the value of