-the pipe, and a signal handler is installed for SIGIO. Every time a SIGIO signal
-is received, the runtime library checks for commands received on the external
-tracing control pipe. The recognized commands are:
+the pipe, and a signal handler is installed for SIGIO (or a carefully chosen
+chainable signal number). Every time such signal is received, the runtime
+library checks for commands received on the external tracing control pipe. The
+recognized commands are: