Hi David, > > Does anyone have a definitive answer for this one? It could be a > > massive > > amount of work for me to rewrite the code if I have to > switch to using > > a single thread for read/write operations. > > Just to clarify, you can use two threads. You can use one for > read and one > for write if you want. However, just like every other shared > object, you > cannot let the SSL connection be modified by one thread while > another thread > is or might be accessing it.
Thanks. That is a relief. (I am using a mutex to prevent any simulataneous operations on a SSL object.) > As for it being a massive amount of work, just replace every call to > SSL_read or SSL_write with a call to check your own queue or > put a message > on your own queue (you can block on 'read' if the queue is > empty and on > 'write' if the queue has too much data in it). Then you have > some sane code > to move data between queues and sockets. You don't mention > your platform(s) > or your performance requirements, so it's hard to give you precise > suggestions. This code has to run on several platforms. Solaris, AIX, Linux and OpenVMS. I haven't evaluated the effort for all possible solutions, but it looks like the current implementation will work. > By the way, using a thread for read and a thread for write, > per client, is > one of the worst possible design patterns. If, for example, > you need to read > a small message from each of 2,500 clients and respond to > them all, about > 5,000 context switches will be needed. It's only suitable if > you totally > don't care about performance. (In which case, just wrap the > SSL_read/SSL_write functions.) I am limited by the architecture of the existing legacy code. Much of it was written before support for threads was widely available. The performance should not be a big issue and we will not have many clients connecting at the same time. Cheers, Mark ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager [EMAIL PROTECTED]
