From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,a0224dc3d1e52f3d X-Google-Attributes: gid103376,public From: stt@houdini.camb.inmet.com (Tucker Taft) Subject: Re: Streams and Concurrency Date: 1998/12/30 Message-ID: #1/1 X-Deja-AN: 427167401 Sender: news@inmet.camb.inmet.com (USENET news) X-Nntp-Posting-Host: houdini.camb.inmet.com References: <76dhm3$rkq$1@nnrp1.dejanews.com> Organization: Intermetrics, Inc. Newsgroups: comp.lang.ada Date: 1998-12-30T00:00:00+00:00 List-Id: It seems clear that the stream attributes do not directly support the logging from multiple tasks, with interleaving occurring only between "top-level" objects, as desired by this application. Furthermore, they don't support reading without waiting. However, it should be simple enough to build a generic package which provides the desired functionality. Each current "top-level" use of a stream attribute in the application would be changed to be a call on a "read/write" or "input/output" routine of an appropriate instance of this generic package. Such a routine would acquire a lock on the stream, invoke the corresponding stream attribute, and release the lock. Furthermore, to support non-blocking read, you would need to add some kind of marker into the stream itself, I suspect, to be placed between "top-level" objects in the stream. Then, when you call the non-blocking "read" or "input" routine of the instance of this generic package, it would call a routine of the underlying stream which would indicate whether there is an "entire" top-level object already buffered up. If not, the non-blocking read/input routine of the generic would return a "not available" indicator. If there is an entire top-level object buffered up, the read/input routine would use the corresponding stream attribute to read the data from the stream, confident that it wouldn't block or get an end-of-file indication during the read. -- -Tucker Taft stt@averstar.com http://www.averstar.com/~stt/ Technical Director, Distributed IT Solutions (www.averstar.com/tools) AverStar (formerly Intermetrics, Inc.) Burlington, MA USA