Non-user threads in output modules

[Lukas Loehrer]

Hi all,

I am in the process of developing an speech dispatcher output module
for espeak. In the sd documentation, it says the following:

"   * If one or more new threads are used in the output module, they
     must block all signals."

My question is what about the threads used by the TTS system
internally? For example, espeak uses a separate thread to call the
callback function for delivering synthesis events. The developer of
the output module does not have control over the properties of such
threads. Does the above requirement also apply to threads used by the
TTS system? What is the reason for the above requirement?

Thanks and best regards, Lukas