"Qingqing Zhou" <zhouqq@cs.toronto.edu> wrote
> As I reviewed the win32/sema.c, there is some code that I am not clear,
can
> anybody explain please?
>
There is another problem related to concurrent operations on win32 sema. Say
two processes are doing semop(+1) concurrently. Look at this code:
/* Don't want the lock anymore */ sem_counts[sops[0].sem_num]++; ReleaseSemaphore(cur_handle, sops[0].sem_op, NULL);
Except for the problem mentioned in the above thread that the first line
should be: sem_counts[sops[0].sem_num] += sops[0].sem_op, the sem_counts[]
are unprotected by anything, so we might lose an update. Maybe I totally
misunderstand something?
Regards,
Qingqing