Hybrid Spin Semaphore API

Most applications won't need to use this class directly. To create a hybrid spin semaphore, you need to use the HybridLock constructor:

HybridLock(sem_loc, mode, initial_value, permissions)

mode is one of:

• CONNECT_OR_CREATE: Connect to an existing semaphore if it exists, otherwise create one.
• CONNECT_TO_EXISTING: Try to connect to an existing semaphore, raising an NoSuchSemaphore if one couldn't be found by that name.
• CREATE_NEW_OVERWRITE Create a new semaphore, destroying the existing one (if one does exist).
• CREATE_NEW_EXCLUSIVE Create a new semaphore, raising a SemaphoreExists exception if one already does.

initial_value is the initial value of the semaphore (1 or 0 are the only values possible). Note that this is only set if creating a new semaphore, this value is otherwise ignored.

permissions is who should be able to access the semaphore. For example, 0666 allows anyone to access the semaphore, whereas 0600 only allows the user who created it (and root) to access it.

Examples

sem = HybridLock(
    'test_location', CREATE_NEW_OVERWRITE, 1, 0666
)
sem.lock(timeout=1)
sem.unlock()

That's pretty much it - at the moment it only supports timeout values in seconds using whole integers.