Serial programming

Jacek Trzcinski
Wed May 23 05:48:00 GMT 2001

I have created patch to serial device which implements ioctl function
manipulate RTS and DTR line and reading modem lines. I will send it when
I sign copyright
assignment form.
I didn't do two things in my patch about I would like discuss here.
First remarks I shared
with Corinna Vinschen and She suggested send e-mail here.

1) To read input queue there should be use constant
FIONREAD (information taken from different sources) but cygwin occupy it
socket software !(it is macro). Constant TIOCINQ I have taken from linux
where it is equal FIONREAD(FIONREAD is not occupied in linux like in
cygwin). As Corinna remarked, this macro
expands to a constant expression but including asm/socket.h in serial
programming seems to make not much sense. She suggested (I support her)
to create asm/ioctls.h file like in Linux.

2) Next matter concerns device name convention. In cygwin one may use
/dev/com1 or /dev/ttyS1 and so on. (what for is utilizing /dev/comx
devices I do not
know - it is not portable to linux).
I think also that number of devices should start from 0 not from 1 thus
devices shold be
numbered /dev/ttyS0, /dev/ttyS1 and so on like in linux because again it
is not portable.
Somebody who had access to /dev/ttyS0 in linux will have not in cygwin !

Best regards

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