Date: Thu, 23 Dec 1999 10:20:04 +0800 From: miaobo@mail.zhongxing.com To: hackers@freebsd.org Subject: ASYCH/message-based programming style Message-ID: <48256850.000933F2.00@mail.zhongxing.com>
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Hi gurus: I am sorry this may be off-topic: I think, compared to the application programming style of Win32, which is asychronize and event/message based, application developing under UNIX is so different. Here under UNIX, I guess the programmers need to take care of all sychronization IPC topics in the code, that is, if a process has 2 TCP socket connection, one pipe, and one SYSV msg id to listen on, the control of program instruction flow will be hard if we don't want access to busy-wait situation, Although we can use select() to solve part of the problem, I think it's not yet enough. And handling asychronize events under UNIX, such as signal delievery and trapping is hard, the logic of the code will be unclear, and we only have one asych timer to use(alarm()/setitimer() share the same timer) and under MT programming we even need to consider sychronization primitives' ASYN signal or cancellation safety. So I wonder if there can be any ASYN mechanism in UNIX application programming in which All incoming I/O and IPC data are represented by events that contains the "pointer" to data itself, which is Win32 style like. This maybe hard that it needs modification on kernel, such as implementation by Solaris2 of POSIX4 aio_read()/aio_write(). Or, just for historical reasons that UNIX just don't have this kind of mechanism? As I think, message-based programs is easier to write and the logic will be clearer. Someone told me that message-based procedures are slower than SYCH ones just like unix does, I don't why they say so if it is true, do you have any comment about this? That is, can anyone introduce the procedures that, from NIC receives a packet to applcation's unix blocked read() returns/win32's application is informed by an event to me? Thanks in Advance! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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