|tag name||v0.8.0pre (69be1297f927f6f0985a1cfb1f4b681b9cf0d5ec)|
|tag date||2011-02-27 11:13:02 +0000|
|tagged by||Eric Wong <firstname.lastname@example.org>|
|tagged object||commit 3308466144...|
posix_mq 0.8.0pre - kinder, gentler and less exceptional
This adds trysend, tryreceive, and tryshift interfaces to avoid exceptions on common EAGAIN errors for non-blocking users. EAGAIN during non-blocking messages is common when there are multiple readers/writer threads/processes working on the same queue. trysend is like send, except it returns true for success and false for EAGAIN. send (still) returns nil, which I now consider a mistake but won't change until post-1.0... tryreceive and tryshift are like receive and shift respectively, but they return nil for EAGAIN and the same return values for their non-shift variants. None of these methods call mq_setattr() beforehand to set the non-blocking flag, it assumes the user set it once before they were ever called and never changes it. Checking/setting the non-blocking flag every time is needless overhead and still subject to race conditions if multiple processes/queues keep flipping flag on the same queue descriptor. These interfaces are not yet final, feedback is appreciated at email@example.com.