rwlock

I have a problem regarding the behaviour of the pthread function pthread_rwlock_wrlock . The specification linked above states that when one thread has locked the lock for writing and the same thread locks it again, it results in undefined behaviour (I could actually observe this in that on x86 Linux calling this function is a noop and on PowerPC Linux it stalls the thread). The behaviour I need would be a read write lock that has the following characteristics: read-locking by a thread succeeds if: the lock is not held by any thread the lock is only read-locked by zero or more threads

I have an object of type Arc<RwLock<SessionData>> And I have a method that is supposed to take some kind of reference to SessionData fn some_method(session: ...) I'm using Rocket (a web-framework for Rust), and I can't directly invoke the method, because it is invoked by Rocket. However, I can provide it with an implementation that creates an object that will be passed to the handler. It looks a bit like this: impl<'a, 'r> request::FromRequest<'a, 'r> for SomeType { type Error = (); fn from_request(request: &'a request::Request<'r>) -> request::Outcome<Self, Self::Error> { // return object