Re: GNAT.Serial_Communications

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

tonyg wrote on comp.lang.ada:
>> Looking at the gnat sercom package it has a total lack of options for
>> flow control. I am going to look at posix packages now and its options
>> with serial interfaces. Does anyone know if Adacore are planning to
>> add some more functionality to this package?
>
> Just to let you all know ( I'm sure the world was waiting with baited
> breath!) that thanks to the help received, its now all working. I'll
> document what the problem was with some additional stuff to let future
> people know.
>
> It was the flow control setting and it can be fixed by opening another
> terminal window and using the command
>
> stty --file=/dev/ttyUSB0 -crtscts
>
> However - any ada program compiled with the gnat serial communications
> package if run again will reset the port to add flow control so this
> needs it will need to be done again. Which is unfortunate for me and
> anyone with non flow control electronics. I expect this will occur
> everytime the port is opened. Out of interest do all you serial port
> tinkerers out there use flow control?

I think you'll have to create a task-specific binding to ioctl(2) to
set the flow control options before writing to the port.  The fact
that ioctl(2) is variadic, non-portable and non-standard may explain
why there is nothing in GNAT.Serial_Communications related to flow
control.

If you're not sure what arguments to pass to ioctl, maybe you can try:

strace stty --file=/dev/ttyUSB0 -crtscts

--
Ludovic Brenta.