Thanks for your reply. Can you write an example with the semaphore in this context? Thanks, Carlo David Sugar ha scritto: I think what he really wants to do is use the Common C++ Semaphore with a count of 1, since semaphore can block with a "timeout", and with a "1" count in effect acts as a mutex...The larger question though of what to do with the stuck thread, perhaps from a broken library, is important also. He could cancel the thread in question if it timed out, and put cleanup code in the thread destructor when he invokes delete to join it, but if the library allocated resources he cannot determine for them to get cleanly deallocated. Conrad T. Pino wrote:You're on the right track. Please pardon my rusty recollection syntax. Revise: mutex.enterMutex(); to a form that accepts a timeout. This example won't compile: const int timeout = 500; while (1) { if ( isPending( pendingInput ) ) { int result = mutex.enterMutex( timeout ); if ( result == success ) { ---> protected function call (a function that can't work in multithread env) <--- mutex.leaveMutex(); } else { // do something else with pending input } } } While the above will implement your timeout idea it does nothing about the fundamental problem. When the library "breaks" can be discoverd and the blocked mutex/thread combination can be cancelled/restared HOWEVER PROPRIETARY LIBRARY STATE IS INCONSISTENT & LIKELY DANGEROUS. If the library is dynamically loaded under your control then unload it and reload it to get it back into a consistent state. If it's auto or static linked then you may have an unsolveable problem. If a reliable system is your goal then one of these MUST be true: proprietary library NEVER fails OR proprietary library can be forced back to a consistent state because it has a reload or reinitialize method Good luck.-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Wakan Sent: Saturday, January 27, 2007 07:18 To: bug-commoncpp@gnu.org Subject: can't release mutex Hi, I'm using commoncpp library in a project that includes a multithread server that can accept many tcp connection and each connection generates a thread. In this server I'm using a thirdy party proprietary library (compiled), that (as the producer says) can't work in multithread environment. As each connection thread needs to call functions of this thirdy party library, I've used a mutex to protect the piece of code where this external library function is called. In this way I can use this library fine, because all calls are serialized and the protected function is called by one thread each time. This is an example: ... while(1) { if(isPending(pendingInput)) { mutex.enterMutex(); ---> protected function call (a function that can't work in multithread env) <--- mutex.leaveMutex(); } } ... in 99% of cases it works fine. But it accidentally happens that a thread can't exit from the mutex maybe because the thirdy party function freezes itself. When this happens, the server can accept other connections, soit still works, but each thread can't enter in the mutex proteced piece of code. I'm thinking about something, like a timeout, that exits the mutex after a time, if the thread is not exiting... Can someone help me to resolve this problem? Are there other solutions? Thanks in advance, Regards Carlo_______________________________________________ Bug-commoncpp mailing list Bug-commoncpp@gnu.org http://lists.gnu.org/mailman/listinfo/bug-commoncpp__________ NOD32 2011 (20070127) Information __________ This message was checked by NOD32 antivirus system. http://www.eset.com |
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