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- Newsgroups: comp.os.os9
- Path: sparky!uunet!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!cbnewsc!cbfsb!cbnewsg.cb.att.com!mdw
- From: mdw@cbnewsg.cb.att.com (mark.d.wuest)
- Subject: Re: how to do concurrent read/write on terminal?
- Message-ID: <1992Sep10.123130.3716@cbfsb.cb.att.com>
- Keywords: input output
- Sender: news@cbfsb.cb.att.com
- Organization: AT&T
- References: <1992Sep9.223924.5962@mcs.anl.gov>
- Date: Thu, 10 Sep 1992 12:31:30 GMT
- Lines: 33
-
- In article <1992Sep9.223924.5962@mcs.anl.gov> saunders@aps.anl.gov writes:
- >I have a control program (in Microware-C) running under OS-9 which
- >accepts commands from /t1 and also periodically writes to /t1.
- >There is a separate fork'ed process for reading commands and
- >for periodic writes. (There are reasons behind this design.)
- >
- >The problem is that the gets() in the consuming process sleeps and prevents
- >the producing process from getting characters out to the terminal.
- >
- >Is there any way of solving this without installing a signal intercept
- >function and grabbing unbuffered characters one at a time with getchar()?
- >That solution is essentially duplicating the driver.
- >
- >Is there some mode I can set that will allow printf's while another process
- >is sitting in gets()? Do I need to open() additional file descriptors?
-
- It is inherent in the scf file manager that you cannot do this. We
- wrote our own file manger for an application because it was so central
- to our project. Without doing that, yes, you have to do the signal
- game. Look at any of the terminal programs (sterm, kermit) for
- examples on how this is done.
-
- This is, to me, one of OS-9's less attractive features. If Microware
- saw it as crucial to a large project (i.e.: "change this feature, and
- we'll buy a 5,000-copy license"), they just *might* change it for you.
- More likely is a custom version of scf that you pay extra for. Even
- more likely is, "This is that way it is. Take it or leave it."
-
- Mark
- --
- Mark Wuest *MY* opinions, not AT&T's!!
- mark.wuest@att.com
- mdw@cheshire.att.com (NeXT Mail)
-