PThreads Programming

Chapter 4. Managing Pthreads

In this chapter:

• Setting Thread Attributes

• The pthread_once Mechanism

• Keys: Using Thread-Specific Data

• Cancellation

• Scheduling Pthreads

• Mutex Scheduling Attributes

In previous chapters, we explored the advantages of multithreaded programs, examined various program design models, and experimented with simple and more complex synchronization mechanisms. Our ATM program is now a full-fledged, well-synchronized multithreaded server, designed after the boss/worker model and optimized to use a thread pool. On our way, we introduced many other Pthreads features in passing. It’s now time to examine these features a little more closely and see how we can use them to enhance our ATM server.

Our agenda includes:

Thread attributes

A thread attribute allows you to create a thread in the detached state. On some systems you can also specify attributes that control a thread’s stack configuration and its scheduling behavior.

The pthread_once mechanism

By using the pthread_once mechanism, you can ensure that an action is performed once—and only once—regardless of how many times the threads in your program attempt to perform it. This function is useful, for instance, when more than one thread shares a file or a procedure and you don’t know which thread will execute first.

Keys

Threads use keys to maintain private copies of a shared data item. A single, globally defined key points to a different memory location, depending upon which thread is executing, thus allowing the thread to access ...