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Top Forums Programming MultiThreading using Pthreads Post 302380162 by Corona688 on Monday 14th of December 2009 11:53:01 AM
Old 12-14-2009
You almost certainly need synchronization somewhere inside ::Receive() to prevent race conditions -- two threads blindly overwriting the same variable, unaware of the other changing it while they were asleep -- but nothing prevents this except whatever synchronization you do yourself. How efficient this is under high load depends on how much waiting the threads have to do for each other to avoid race conditions. If Receive() does a lot of processing before actually altering or using the object members in any way, most of that could happen concurrently, but if all it does is update the object, almost nothing should happen concurrently, making the threads mostly pointless.

Polling isn't a good idea in either case though, given a better alternative: Have you tried select()? It can wait for activity on an entire set of file descriptors without polling. Once activity happens, you can hand the file descriptor it reports off to a thread for processing if advantageous, or just feed it to Receive() if not.

Last edited by Corona688; 12-14-2009 at 01:01 PM..
 

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thr_join(3C)						   Standard C Library Functions 					      thr_join(3C)

NAME
thr_join - wait for thread termination SYNOPSIS
cc -mt [ flag... ] file...[ library... ] #include <thread.h> int thr_join(thread_t thread, thread_t *departed, void **status); DESCRIPTION
The thr_join() function suspends processing of the calling thread until the target thread completes. The thread argument must be a member of the current process and cannot be a detached thread. See thr_create(3C). If two or more threads wait for the same thread to complete, all will suspend processing until the thread has terminated, and then one thread will return successfully and the others will return with an error of ESRCH. The thr_join() function will not block processing of the calling thread if the target thread has already terminated. If a thr_join() call returns successfully with a non-null status argument, the value passed to thr_exit(3C) by the terminating thread will be placed in the location referenced by status. If the target thread ID is 0, thr_join() finds and returns the status of a terminated undetached thread in the process. If no such thread exists, it suspends processing of the calling thread until a thread for which no other thread is waiting enters that state, at which time it returns successfully, or until all other threads in the process are either daemon threads or threads waiting in thr_join(), in which case it returns EDEADLK. See NOTES. If departed is not NULL, it points to a location that is set to the ID of the terminated thread if thr_join() returns successfully. RETURN VALUES
If successful, thr_join() returns 0. Otherwise, an error number is returned to indicate the error. ERRORS
EDEADLK A joining deadlock would occur, such as when a thread attempts to wait for itself, or the calling thread is waiting for any thread to exit and only daemon threads or waiting threads exist in the process. ESRCH No undetached thread could be found corresponding to the given thread ID. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
thr_create(3C), thr_exit(3C), wait(3C), attributes(5), standards(5) NOTES
Using thr_join(3C) in the following syntax, while (thr_join(0, NULL, NULL) == 0); will wait for the termination of all non-daemon threads, excluding threads that are themselves waiting in thr_join(). SunOS 5.10 27 Mar 2000 thr_join(3C)
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