NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/sys/amiga/programmer/7061

Internet Message Format | 1996-08-05 | 1.7 KB

Path: sparky.navsea.navy.mil!matuli_a
From: [e-mail] (Alex Matulich 03T1 602-6691)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Messages vs. Semaphores for external clocking
Date: 8 Apr 1996 14:02:42 GMT
Organization: Naval Sea Systems Command Code 03T1
Message-ID: <4kb6a2$[e-mail]>
References: <4ju349$[e-mail]> <4jvrqs$[e-mail]> <[e-mail]> <[e-mail]>
NNTP-Posting-Host: marlin.navsea.navy.mil

Laurent GIROUD  <[e-mail]> wrote:
}> > Use global data, which your subtask fills with the timer-values,
}> > and the parent process reads. Disable() and Enable() multitasking

}> This is very, very bad advice. A message port or a semaphore is indeed
}> needed. Disable()/Enable() are bad programming styles, especially for

}   Of course but you must not forget something -> in order to be sure
}that the semaphore you are just refering to in your program is valid
}you actually HAVE to FindName() it before and then to acces it in an
}atomic operation thus needing to embrace the two instructions (FindName
}+ ObtainSemaphore) in a Forbid()/Permit() pair...

Now, I didn't know this.  I thought FindName() was something I had to do
only once, and thereafter I could access the semaphore whenever I pleased,
locking it and unlocking it as needed.

Other people's suggestion to use a double-buffered semaphore sounds
interesting, and might increase eficciency.

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Alex Matulich                      __.  __=#||  ___   _o--
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