Exiting a Thread

The pthread_exit library call terminates a thread in much the same manner as a call to exit terminates a process. The pthread_exit library call is shown in Table 11.2.

The pthread_exit library call takes a single argument, a reference to a retval value. This reference is returned when a nondetached thread is exited. Upon termination, the thread releases its thread-specific (but not process-specific) resources. If the thread was nondetached, its status information and thread ID are kept by the system until a join is issued or the creating process terminates. When the function being executed by the thread performs a return (implicitly or explicitly), the system implicitly calls pthread_exit .

Table 11.2. The pthread_exit Library Function

Include File(s)

Manual Section

3

Summary

void pthread_exit (void * retval);

Return

Success

Failure

Sets errno

This call does not return

   

In Chapter 3, Section 5, "Ending a Process," the atexit library function was presented. This function allows the user to specify one or more user -defined functions to be called in a LIFO (last-in, first-out) manner when the process exits. In asimilar vein there is a small suite of pthread cleanup calls that can be usedto specify and manipulate user-defined functions that are called when athread exits. In this grouping are the calls pthread_cleanup_pop , whichremoves a function from the cancellation cleanup stack, and thread_cleanup_push , which pushes a function on the cancellation stack of the current thread. Additionally, nonportable versions of these functions (called pthread_cleanup_pop_restore_np and pthread_cleanup_push_defer_np ) are provided. A full discussion of these functions is beyond the scope of this text.

Programs and Processes

Processing Environment

Using Processes

Primitive Communications

Pipes

Message Queues

Semaphores

Shared Memory

Remote Procedure Calls

Sockets

Threads

Appendix A. Using Linux Manual Pages

Appendix B. UNIX Error Messages

Appendix C. RPC Syntax Diagrams

Appendix D. Profiling Programs





Interprocess Communication in Linux
Interprocess Communications in Linux: The Nooks and Crannies
ISBN: 0130460427
EAN: 2147483647
Year: 2001
Pages: 136
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