Sometimes people are actually interested in using timers, instead; timers are provided by Xt, which Motif uses, and are non-interrupting. They are dispatched when Xt handles events. See http//www.motifzone.com/resources/man/XtAppAddTimeout.html for information.

Alternatively, you can interrupt your application with a signal, and when Xt handles events it can alert your application that the signal has fired, and you can take appropriate, applicaton-specific action. See http//www.motifzone.com/resources/man/XtAppAddSignal.html for information.

And, finally, you may be talking about using threads in your application. See http//www.motifzone.com/resources/man/XInitThreads.html for some of the details.