Книга: Microsoft Windows Embedded CE 6.0 Exam Preparation Kit

Lesson Summary

Lesson Summary

Windows Embedded CE is a multithreaded operating system that provides several process management functions to create processes and threads, assign thread priorities ranging from zero through 255, suspend threads, and resume threads. The Sleep function is useful in suspending a thread for a specified period of time, but the WaitForSingleObject or WaitForMultipleObjects functions can also be used to suspend a thread until another thread or a synchronization object is signaled. Processes and threads are ended in two ways: with and without cleanup. As a general rule, always use ExitProcess and ExitThread to give the system a chance to perform cleanup. Use TerminateProcess and TerminateThread only if you have absolutely no other choice.

When working with multiple threads, it is beneficial to implement thread synchronization in order to coordinate access to shared resources within and between processes. Windows Embedded CE provides several kernel objects for this purpose, specifically critical sections, mutexes, and semaphores. Critical sections guard access to resources within a single process. Mutexes coordinate mutually exclusive access to resources shared among multiple processes. Semaphores implement concurrent access by multiple threads to resources within a process and between processes. Events are used to notify the other threads, and interlocked functions for the manipulation of variables in a thread-safe atomic way. If you happen to encounter thread synchronization problems during the development phase, such as deadlocks, use the CeLog event-tracking system and Remote Kernel Tracker to analyze the thread interactions on the target device.

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