Semaphores in unmanaged code

Question

I've been using the Semaphore class to create semaphores. However, the examples use managed code (requires /clr), and I need to use unmanaged code because it seems FreeType doesn't like working with managed code.

How can I create two simple threads which use a semaphore in unmanaged code?

Answer 1

You may try and use Boost.interprocess. It provides semaphores. See here.

Answer 2

Use native Windows semaphore objects.

Answer 3

You want CreateSemaphore which is implemented in kernel32. The general pattern is to create a name or unnamed semaphore object to use from both threads. You can use OpenSemaphore to get a handle to an existing named semaphore. Set the initial count and maximum counts on your semaphore appropriately then use one of the Wait Functions to take a logical lock on your shared resource by decrementing the count on your semaphore. When your thread has finished with the resource, call ReleaseSemaphore to increment the available lock count.