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From: aries@skorpio.usask.ca (Aries Project)
Newsgroups: comp.sys.amiga.tech
Subject: RE: Problems with serial device in shared mode
Message-ID: <1989Oct25.175549.16677@dvinci.usask.ca>
Date: 25 Oct 89 17:55:49 GMT
Reply-To: aries@skorpio.usask.ca (Aries Project)
Distribution: na
Organization: University of Saskatchewan, Saskatoon, Canada
Lines: 37

Subject: Re: Problems with serial device in shared mode
Newsgroups: comp.sys.amiga.tech
References: <8910240641.AA22293@postgres.Berkeley.EDU>

From article <8910240641.AA22293@postgres.Berkeley.EDU>, by dillon@POSTGRES.BERKELEY.EDU (Matt Dillon):
> 
> 	I do this all the time (have one program hold the serial device
>     open whilst I execute another).  Are you sure you are using the 
>     1.3 serial.device ???
> 
> 	There is a problem... many terminal programs and other programs
>     do not open the serial.device SERF_SHARED !! THIS IS WRONG!  You
>     programmers out there, ALWAYS OPEN SERIAL.DEVICE SERF_SHARED !!
> 
> 	The other problem is that the serial.device will refuse to
>     do a SDCMD_SETPARAMS call while active requests are pending, so
>     if you do use something similar to what I've described above you
>     have to be sure that the first program doesn't have any active
>     requests when it executes the second program.
> 
> 					-Matt

I am indeed using the 1.3 serial.device, and I've also tried the new
1.3.2 serial.device.  Both of my programs open the serial device in
shared mode and when I open it for the second time the first program
is in a suspended state and has no active requests.

Here's some background info.  The main program using the serial port
is a souped up aux handler.  When I want to do a file transfer, I
suspend the operations of the aux handler and have the protocol open
a second incarnation of the serial device.  When the transfer is
finished, the handler resumes its operations.  This works just fine
90% of the time, but all too frequently I lose DTR when the protocol
tries to open the serial device.  I am currently forcing DTR and
things work fine, but I want to hang up by dropping DTR...

			-Mike Oliphant