Does Amiga OS 4.x have a pthreads rwlock implementation?

I'm using POSIX threads rwlocks in a non Amiga OS project. Since I'm interested in eventually having it running on Amiga OS 4.x too I had a look at pthread.h for Amiga OS 4.x, and it's missing rwlock functionality. Pthreads semaphores are also no-where to be seen. Do we have an implementation of these?

Amiga OS semaphores are similar, with the exception that a thread can upgrade/downgrade a shared lock to an exclusive lock, whereas trying this with a semaphore will cause a deadlock.

Another matter is using pthreads from within an Amiga OS library. IIRC, there may be some issues with this. Is it possible with the threads.library? Or should POSIX threads not be used in this case?

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