On Tue, Aug 14, 2012 at 3:44 PM, Matthew Knepley <knepley@gmail.com> wrote:

You can, but the setter routines interpret NULL as "ignore", i.e.

if (func) ctx->func = func;

Does this make sense to anyone? Can we remove that if?

Then we would have to revisit lots of locations and get the old value before resetting it. Passing NULL was a convenience.