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Top Forums Programming sockets - can you send data while waiting on select() Post 302526639 by expl on Wednesday 1st of June 2011 06:11:45 AM
Old 06-01-2011
Sockets are also not available on EVERY system, does not mean you should not use them. The option is available on Windows, Linux and BSDs, haven't checked more.

Go check the POSIX specification for socket's options. The STANDARD said so.

---------- Post updated at 05:11 AM ---------- Previous update was at 04:38 AM ----------

Quote:
Originally Posted by Loic Domaigne

Your reasoning is excellent, but your basic assumptions are off. If you read carefully my posts, I just mentioned that it is possible to block on a socket, while sending data, since TCP is full-duplex. Nothing more, nothing less.

And even if people err (I personally do), I don't feel the need to treat them "maroons that have no idea about what they're talking about". We're all here to learn, and this can be achieved in a respectful way.

Just my 2c,
Loïc
I apologize for my rudeness.

As in abstract implementation goes, it is possible but its not very smart as it is easy to mess up, consider blocking thread unblocks (because it gets data to read) while other thread is sending and starts sending as well, you end up with borked output, or at least there will be a race condition possibility. Smart implementation should use just one thread per connection handler.

Last edited by expl; 06-01-2011 at 07:00 AM..
 

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PTHREAD_SUSPEND_NP(3)					   BSD Library Functions Manual 				     PTHREAD_SUSPEND_NP(3)

NAME
pthread_suspend_np, pthread_resume_np -- suspend/resume the given thread LIBRARY
POSIX Threads Library (libpthread, -lpthread) SYNOPSIS
#include <pthread.h> int pthread_suspend_np(pthread_t thread); int pthread_resume_np(pthread_t thread); DESCRIPTION
The pthread_suspend_np() function suspends the thread given as argument. If thread is the currently running thread as returned by pthread_self(3), the function fails and returns EDEADLK. Otherwise, it removes the named thread from the running queue, and adds it to the suspended queue. The thread will remain blocked until pthread_resume_np() is called on it. In other words, pthread_resume_np() resumes the thread given as argument, if it was suspended. RETURN VALUES
Both functions return 0 on success and an error number indicating the reason for the failure. COMPATIBILITY
These functions are non-standard extensions. ERRORS
The pthread_suspend_np() function may fail if: [EDEADLK] The thread requested to suspend was the currently running thread. [ESRCH] The supplied thread was invalid. The pthread_resume_np() function may fail if: [ESRCH] The supplied thread was invalid. NOTES
Some pthread_suspend_np() implementations may allow suspending the current thread. This is dangerous, because the semantics of the function would then require the scheduler to schedule another thread, causing a thread context switch. Since that context switch can happen in a sig- nal handler by someone calling pthread_suspend_np() in a signal handler, this is currently not allowed. In pthread_resume_np() the NetBSD implementation does not check if the thread argument is not already suspended. Some implementations might return an error condition if pthread_resume_np() is called on a non-suspended thread. SEE ALSO
pthread_attr_setcreatesuspend_np(3), pthread_self(3) BSD
July 9, 2010 BSD
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