Gerhard Fuernkranz wrote:
If open() blocks on a serial port, then a typical reason is that modem control is enabled for this tty (i.e. the CLOCAL flag not set, see "man termios"), but the attached device does not assert the DSR signal. I.e. open() waits until the device reports "I am ready".Invoke "stty -a -F /dev/ttyS2" in order to check the settings of the tty. Look for "clocal" (-> no modem control) versus "-clocal" (-> modem control) in the output.
Hi Gerhard, is there anything I could do from a progromatic point of view to avoid such a hang ? Presumably I don't want to alter the CLOCAL flag for a serial port that isn't connected to an instrument. Perhaps there's a better way of getting a list of potential instrument serial ports that doesn't involve opening them ? cheers, Graeme.