Operating systems threads lab
The tthreads package is a non-preemptive user mode threading library. This document describes how it is intended to be used. Its API is also documented online
Step 1: makeThreads initializes the thread system. It must be called prior to any other functions from the tthreads library.
Step 2: createThread creates a new ready thread. It can be called anytime after makeThreads. createThread takes two arguments, the address of the function that the thread will call upon beginning execution and its parameter. A thread terminates when that function returns.
Step 3: startThreads starts the threading system by scheduling one of the ready threads. startThreads returns when either (1) all threads have terminated or (2) the thread system has deadlocked. The thread system is deadlocked when there are unterminated threads and no threads are ready.
Notes
- A thread may call yield at any time. A call to yield changes the running (calling) thread's state from running to ready.
The mutex library implements a blocking binary semaphore of type Mutex that controls access to a singleton resource. The interface is described below.
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mutexInit initializes the Mutex with its initial availability (either 0 if unavailable or non-zero if available).
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mutexLock requires access to the resource. If the resource is unavailable the thread will block until the thread is granted access.
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mutexUnlock releases the resource thereby making it available to be locked in the future.