extensions (@pxref{multiprocess extensions}) are supported, actions
can be specified to match all threads in a process by using the
@samp{p@var{pid}.-1} form of the @var{thread-id}. An action with no
-@var{thread-id} is called the default action and matches all threads.
-Specifying multiple default actions is an error; specifying no actions
-is also an error.
+@var{thread-id} matches all threads. Specifying no actions is an
+error.
Currently supported actions are: