Multiple-writer thread-safe queue in C

Question

I am working on a multi-threaded C application using pthreads. I have one thread which writes to a a database (the database library is only safe to be used in a single threa

Answer 1

If you dont need a lock free queue, then you could just wrap up an existing queue with a lock.

Mutex myQueueLock;
Queue myQueue; 
void mtQueuePush(int value)
{
    lock(myQueueLock);
    queuePush(myQueue, value);
    unlock(myQueueLock);
}
int mtQueueNext()
{
    lock(myQueueLock);
    int value = queueFront(myQueue);
    queuePop(myQueue);
    unlock(myQueueLock);
    return value;
}

The only thing after that is to add some sort of handling for mtQueueNext when the queue is empty.

EDIT: If you have a single reader, single writer lockless queue, you only need to have a lock around mtQueuePush, to prevent multiple simultaneous writers.

There are a number of single reader/writer lockless queues around, however most of them are implemented as c++ template classes. However do a google search and if need be work out how to rewrite them in plain C.