Deprecated: Control.Concurrent.QSem will be removed in GHC 7.8. Please use an alternative, e.g. the SafeSemaphore package, instead.
Simple quantity semaphores.
Simple Quantity Semaphores
QSem is a simple quantity semaphore, in which the available
"quantity" is always dealt with in units of one.
Build a new
QSem with a supplied initial quantity.
The initial quantity must be at least 0.