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From: gil@ginger.sri.com (Gil Porat)
Newsgroups: comp.sys.mac.programmer
Subject: FSRead hangs on the serial driver
Message-ID: <7770@unix.SRI.COM>
Date: 9 Jan 90 20:10:31 GMT
Sender: news@unix.SRI.COM
Reply-To: gil@ginger.sri.com (Gil Porat)
Organization: SRI International
Lines: 31


I have a problem with reads hanging on the serial driver.
Here are the facts.

1) My serial device, connected to the modem port of the
   mac, will transmit 80ish bytes when asked to do so.

2) I instruct my serial device to transmit.

3) I call FSRead successively with the serial port reference
   number and a request for 64 bytes.

   The first time through I get 64 bytes returned in my buffer,
   but the second time the FSRead hangs indefinitely.  


My questions are...

1) Why does the second FSRead hang?

2) Doesn't FSRead return as much as it can?

3) Is there a way to get the serial driver and/or FSRead to time out?

4) Does FSRead need an EOT to return?

Any help will be greatly appreciated.

Gil Porat
gil@ginger.sri.com
(415)323-2053