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Plan 9 has a very interesting synchronization mechanism, the rendezvous() call. A good property of this is that you don't need to explicitly initialize and destroy a barrier object, unlike as with e.g. POSIX barriers (which are mandatory to begin with). Upon "meeting", they can exchange a value. This mechanism will be nice to synchronize certain stages of initialization between threads in the following commit. Unlike Plan 9 rendezvous(), this is not implemented with a hashtable, because that would require additional effort (especially if you want to make it actually scele). Unlike the Plan 9 variant, we use intptr_t instead of void* as type for the value, because I expect that we will be mostly passing a status code as value and not a pointer. Converting an integer to void* requires two cast (because the integer needs to be intptr_t), the other way around it's only one cast. We don't particularly care about performance in this case either. It's simply not important for our use-case. So a simple linked list is used for waiters, and on wakeup, all waiters are temporarily woken up.
9 lines
131 B
C
9 lines
131 B
C
#ifndef MP_RENDEZVOUS_H_
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#define MP_RENDEZVOUS_H_
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#include <stdint.h>
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intptr_t mp_rendezvous(void *tag, intptr_t value);
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#endif
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