Subject: open () and /dev/ttyS0
From: Craig Gullixson <[email-masked]>
To: [email-masked]
Cc: [email-masked]
Date: Wed, 24 Sep 2003 15:03:20 -0600 (MDT)

I have an application where I need to communicate with some simple
controllers via serial commands.  I have a package to do the low level
open,read,write, and close tasks for a tty port that I have been using
for a number of years under Solaris using the standard POSIX tty calls.

My problem is that when attempting to open /dev/ttyS0, I get a
permission denied error.  I get the same error when attempting to
open /dev/com1.  Curiously, the open works when opening "com1" but
the tcgetattr () call then fails with a not a typewriter error
(presumably ENOTTY).

I can manually communicate with the controllers via hyperterm.

My configuration is 

uname -a output:

CYGWIN_NT-5.0 dlsppc 1.5.5(0.94/3/2) 2003-09-20 16:31 i686 unknown unknown 
Cygwin

The windows system is:

Windows 2000 Professional Ver 5.0 Build 2195 Service Pack 4

built on a FAT32 partition.

I have noted several similar problems with opening serial ports in the
archives but have not see anything regarding this being resolved.

Any suggestions would be appreciated.

---Craig

________________________________________________________________________
Craig A. Gullixson
Instrument Engineer			INTERNET: [email-masked]
National Solar Observatory/Sac. Peak    PHONE: (505) 434-7065
Sunspot, NM 88349 USA                   FAX: (505) 434-7029

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