lockShared

Function parameters

Parameters

rwl:*DefaultRwLock

Single-threaded applications use this for deadlock checks in

Types

SingleThreadedRwLock: Single-threaded applications use this for deadlock checks in
PthreadRwLock
DefaultRwLock

Attempts to obtain exclusive lock ownership.

Functions

tryLock: Attempts to obtain exclusive lock ownership.
lock: Blocks until exclusive lock ownership is acquired.
unlock: Releases a held exclusive lock.
tryLockShared: Attempts to obtain shared lock ownership.
lockShared: Obtains shared lock ownership.
unlockShared: Releases a held shared lock.

Source

Implementation

pub fn lockShared(rwl: *DefaultRwLock) void {
    var state = @atomicLoad(usize, &rwl.state, .seq_cst);
    while (state & (IS_WRITING | WRITER_MASK) == 0) {
        state = @cmpxchgWeak(
            usize,
            &rwl.state,
            state,
            state + READER,
            .seq_cst,
            .seq_cst,
        ) orelse return;
    }

    rwl.mutex.lock();
    _ = @atomicRmw(usize, &rwl.state, .Add, READER, .seq_cst);
    rwl.mutex.unlock();
}