Re: thread safety for binding issues

Bless You! It still segfaults all over the place (which is another story), but that particular call_user_function() now works, thanks :) and happy easter egg searching ;) - Markus On Sun, Mar 31, 2002 at 01:11:27PM +0300, Zeev Suraski wrote : > At 20:59 30/03/2002, Markus Fischer wrote: > > Yes, exactly. > > Ok, in that case, by default this won't work 'very nicely' with PHP > (because it's not very standard), but you should be able to get it to work > relatively easily. > > The problem: > > All of PHP's resources (globals, memory management, resource lists, > basically everything) are locked to a specific thread. If you use all of > the standard macros (TSRMLS_FETCH(), TSRMLS_DC, etc.) then your code lives > entirely within the thread in which it's running, and cannot access > anything from other threads. > > > The solution: > > If you need to manipulate resources of another thread, you can do so, but > you have to do a bit of hacking on your own. > > 1. When you register the callback, you have to remember which thread you'd > want to interface with when the callback is called. You can obtain the > thread id by using tsrm_thread_id(): > THREAD_T thread_id = tsrm_thread_id(); > > You have to store this information in a place which would be later > accessible from the callback. > > 2. inside the callback, don't use TSRMLS_FETCH(). Instead, use the > following line of code: > > void ***tsrm_ls = (void ***) ts_resource_ex(0, &thread_id); > > 3. It's important to remember that there are some things that you must not > do inside your callback, due to mutual exclusion problems. For instance, > doing any 'writes' to the resource lists, or even the memory manager - is > likely to cause a crash due to race conditions with the thread that owns > these resources. As long as you limit yourself to read-only data, it > should be fine (even though I don't think we ever made sure that the data > structures are safe for reading while another thread writes to them). > > That's about all I can tell you, other than good luck, and don't do it > unless you really have to :) > > Zeev > > > -- > PHP Development Mailing List <http://www.php.net/> > To unsubscribe, visit: http://www.php.net/unsub.php -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc "Mind if I MFH ?" "What QA did you do on it?" "the usual?" "ah... none :)"