You have to write the non-busy wait handlers yourself. As an example the thread that has acquired the DB and has performed its writes. At the time it commits it could post a condition variable/mutex pair.
Any thread that gets a busy could simply undo its work, and wait on the condition variable. Once it gets the condition variable it goes about performing a retry.. The code is left as an excercise for the reader. This can be really really hard to implement successfully, consider error handling in the case were the thread that has the "lock" suddenly aborts (assuming pthreads and its detached) then no harm to the process. But the other threads will never be signalled either, then they will be stuck. HTH, Ken Andreas Volz <[EMAIL PROTECTED]> wrote: Am Wed, 9 Jan 2008 10:20:31 -0800 (PST) schrieb Ken: > Definately use 3.5.4. > > Not sure how to determine at compile time if the threadsafe part is > enabled. You can always compile yourself to guarantee its set, thats > what I do. > > sqlite will lock the database file for you automatically. Your > threads do not need to implement locking. But they do need to handle > in some fashion. SQLITE_BUSY and/or SQLITE_LOCKED error codes. > > You should also look at "Begin", "Begin Exlusive" and "Begin > Immediate" sql commands. Ok, I found the docs. But I exec only single SQL queries at the moment. So I think I don't need that. > As a user you don't get to pick the lock state, sqlite does that > automatically for you. You must handle the return codes suche as > SQLITE_BUSY, SQLITE_LOCKED etc. Now I implemented a multi-threading example that reads and writes in a database file. Currently I check return values and if in BUSY or LOCKED state I wait some time and try it again until I get the lock. It works, but currently I have around 20 BUSY operations for 5 successful write operations in 5 threads parallel threads. Is it really the way of choose to do it this way? Isn't there a way without active waiting? I would prefer exec() blocking until I get a write lock to not have to loop with a sleep until it works. regards Andreas ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
