Clarion 6: Threading - 2 2002-12-15 -- Andy Ireland Newsgroups: softvelocity.products.c55ee Hi Arnor, > Thanks for the clarification. But how would you pass variables around > between procedures on different threads? Say you have a window on > thread 2 and another window on thread 3 and they need to be accessing > the same data, how would that best be done? I've thought that you > could perhaps use a non-threaded class that has these vars as > properties and then use methods to update/retrieve the data, but > wouldn't that have the same non-safe status as global variables? I.e. > couldn't two threads be trying to update the same class prop at the > same time? This is a flaw in clarion. A thread when created takes a long not a string. It should have been a long and not a string and I hope it has changed. You could however pass the address of something in the string. You should actually keep each thread distinct for the most part but you could always hand off using synchronisation. Why would threaded windows need to access the same data? Why not one threaded window and the others called from it SDI? If we're talking about application configuration data, then this can be global and read only. If a thread needs to change it, sync the change and send an app messate informing other threads it has changed. It would not have the same status if wrapped using something like a reader / writer lock or a spinlock again things that have not been discussed. This threading change has been greatly oversimplified by nearly everyone. The simplest change is to put a critical section around the methods but this will just cause your app to block across all accessing threads which is not always ideal. Most MDI apps do not share data across threads, unless it is mutexed or is read only. However because people have been used to doing this for a long time, I think this will actually cause more problems for clarion programmers than had the change happened when Win95 came out. People will need to do some learning. Regards Andy Plugware Solutions.com Ltd, taking the puzzle out of I.T Tel : +44 1249 813335 Fax : +44 1249 813462 Printed November 23, 2024, 6:54 am This article has been viewed/printed 35319 times. Google search has resulted in 7 hits on this article since January 25, 2004. |