alt Hacker NewsIs the difference between the NT-style and POSIX-style semaphores essentially just that NT (and now this new API in Linux) supports setting a max value? Why don't POSIX semaphores support this?
Is the difference between the NT-style and POSIX-style semaphores essentially just that NT (and now this new API in Linux) supports setting a max value? Why don't POSIX semaphores support this?
WaitForMultipleObjects is fascinating behind the scenes. A single thread can wait on up to 64 independent events, which is done by plumbing the KTHREAD data structure with literally 64 slots for dispatcher header stuff, plus all the supporting Ke/dispatcher logic in the kernel.
There’s never been a POSIX equivalent to this. It requires sophisticated kernel support and the exact same parity can’t be achieved in user space alone.