stty < /dev/modem blocks???

Michel Lanners mlan at
Thu Sep 16 17:22:41 EST 1999

On  15 Sep, this message from Randall R Schulz echoed through cyberspace:
> As you know, the less-than (<) operator in all Unix shells opens the 
> file name given as an argument before it executes the command. In 
> order for an open() call on a TTY device to complete, the RS232 
> hardware signals that indicate the presence of an active device 
> connected to the port. In practice, this means that the DTR (data 
> terminal ready) signal must be asserted before the open call will 
> return.

OK, this sounds right, but how do you explain that I can get at the tty
settings with

stty -a < /dev/ttySx

for both of my serial ports, with absolutely nothing connected to them?



Michel Lanners                 |  " Read Philosophy.  Study Art.
23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
L-1710 Luxembourg              |
email   mlan at            |        |                     Learn Always. "

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