什么是Linux的/ dev / usb / lp0的OSX版本？

Question

I'm writing to a centronics cable and blinking some LEDs via a simple "bufferized" circuit.

I'm able to write out the bits via C code referencing the device location on /dev/usb/lp0 on an Ubuntu machine.

However, I'd like to be able to do this on OSX Mavericks. I don't see the same type of device file as I do in Linux.

ie is there an OSX analog to /dev/usb/lp0 on Linux?

Thanks much.

Answer 1

Under the concept of "everything's a file" lp0 is just a special file that allows raw access to a device, in this case a 'special character file' for the first parallel device. The same would exist on OSX if a driver was present that matched the device, or something like /dev/parport0 . OSX has a pretty limited collection of parallel drivers though. You could try to fudge it - create a 'character' device file pointing it to some generic parallel driver with mknod .

eg mknod lp0 cxy where x an y are the major and minor numbers for the device type. Typically you find these numbers in the documentation/devices.txt file on linux, not sure where this info is on OSX though.

I've seen devices handle this using generic printer drivers, such as a "gadget printer": https://www.kernel.org/doc/Documentation/usb/gadget_printer.txt

(my initial assumption)

In this case the device will actually show up on the system as a printer. You can find a list of printers and their location using CUPS utilities like lpstat:

https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/lpstat.1.html#//apple_ref/doc/man/1/lpstat

There's also the environment variables LPDEST and PRINTER which should list the default print location:

echo $LDPEST