+ const char *key
+ const char *val
+
+# In ZOOM-C, the `val' parameter is const char*. However, our typemap
+# treats this as T_PV, i.e. it's "known" that it points to a
+# NUL-terminated string. Instead, then, I here use opaquechar*, which
+# is an opaque pointer. The underlying C function can then use this
+# along with `len' to Do The Right Thing.
+#
+# TESTED