I am using the latest synaser (007.005.002) from the synapse library which works just fine with (USB) serial ports on Linux and Windows but Mac OSX 10.6 it is proving problematic.

The call which opens the port (synaser.pas:946) is:

  FHandle := THandle(fpOpen(FDevice, O_RDWR or O_SYNC));

where in my case, FDevice is /dev/tty.usbserial.DCUIYCH4.

This fpOpen call blocks indefinitely (i.e. it never returns).

The device is present, working and requires no flow control:

My-Mac:~ admin$ stty -f /dev/tty.usbserial-DCUIYCH4 -a speed 9600 baud; 0 rows; 0 columns;
lflags: -icanon -isig -iexten -echo -echoe -echok -echoke -echonl -echoctl -echoprt -altwerase -noflsh -tostop -flusho -pendin -nokerninfo -extproc
iflags: -istrip -icrnl -inlcr -igncr -ixon -ixoff -ixany -imaxbel -iutf8 -ignbrk -brkint -inpck -ignpar -parmrk
oflags: -opost -onlcr -oxtabs -onocr -onlret
cflags: cread cs8 -parenb -parodd hupcl -clocal -cstopb -crtscts -dsrflow -dtrflow -mdmbuf
cchars: discard = ^O; dsusp = ^Y; eof = ^D; eol = <undef>;

	eol2 = <undef>; erase = ^?; intr = ^C; kill = ^U; lnext = ^V;
	min = 1; quit = ^\; reprint = ^R; start = ^Q; status = ^T;
	stop = ^S; susp = ^Z; time = 0; werase = ^W;

and the screen command opens and communicates via this port just fine so I don't believe there is anything wrong with the device, the driver or the state of any port flags when fpOpen is attempted.

Can anyone tell me what I might be doing wrong here?

Note that adding the O_NONBLOCK flag allows the fpOpen to succeed but all subsequent attempts to talk to the port return ENOTTY which is of course wrong as it is a real (USB) serial (TTY) device.

I'm building with FPC 2.4.2 binaries and sources (for Mac) and it's an FTDI serial device I'm dealing with. Any and all advice most welcome.

Cheers, Bruce.

Have you tried setting clocal under oflags? If "open" thinks it's a modem, then it can block until it sees carrier detection. I notice that my serial ports have clocal set.

This should have helped for the modem issue. Did you remove the O_SYNC? Maybe setting clocal after opening will help?

Henry

Thanks Henry, I've found the problem, more than one actually.

For the record if anyone else runs into this is that the red-herring here was another bug in synaser.pas (007.005.002) where an incorrect ioctl call is made (in Darwin), fixed on line 1939 with:

- SerialCheck(fpioctl(FHandle, TCIOflush, TCIOFLUSH));
+ SerialCheck(fpioctl(FHandle, TCIOflush, Pointer(PtrInt(TCIOFLUSH))));

This bug resulted in the purge that's called after the port is opened to fail resulting in my client code being erroneously told the open failed. Inspection of errno revealed the real problem (EINVAL).

Thanks for the tips and just to confirm the open call I now use (on line
946) which works in Darwin (subject to the ioctl fix above) is:

 FHandle := THandle(fpOpen(FDevice, O_RDWR or O_SYNC or O_NONBLOCK));

which opens successfully and allows the other termio flags to then be set appropriately. My earlier comments about ENOTTY were erroneous.

Bruce.