Re: Problem with fopen, linux, and RS-232, possibly

alp_at_linuxfarms.com
Date: 12/09/04 

Date: 8 Dec 2004 17:02:46 -0800

Hi Gregory,

Are those pins you specified the DCD signal?
I am not sure how fopen() is calling open(), but you want to make sure
open() is called WITHOUT the O_NDELAY flag.
Also, you may want the O_NOCTTY flag to be present.

Try writing the program using open() instead, and specify the exact
flags.
You can also pass fcntl()s to the device.

If this is not DCD signal, and rather some obscure pins than the driver
may be unaware of its "readiness", then any open() call may not block.
Whether the device is actually capable of sending data or not. I
haven't checked the serial pinout to verify.

Here is some reading that may be of assistance.
http://www.easysw.com/~mike/serial/serial.html#2_5
Hope this helps.

Art Perry
Linux Systems/Software Engineer

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