Experimental Physics and
Industrial Control System

Maybe I'm not understanding.  What is the lifetime of the handle returned by taskSpawn()?  Will it ever be free()'d?  Will it ever be reused?  eg. Will a second call to taskSpawn() ever return the same ID?

My assumption is that IDs are not free()d, and can be reused (like a file descriptor).  If this is the case, then it is possible for a race to occur between the time I get hold of an epicsThreadId, and the time I call epicsThreadMustJoin() on it.  If in this interval the original thread exits, and suppose a new thread is started which happens to get the same ID.  In this case I end up trying to join a different thread!

Resolving this is what necessitates joinable vs. detached as user configuration.  Either the handle should remain valid, for the same thread, until joined.  Or it should be freed  immediately when the thread returns.

So the fact that the vxWorks epicsThreadCreateOpt() does nothing with epicsThreadOpts::joinable tells me that there is a bug.

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