Tricky USB device.

[Bernd Walter]

On Fri, Apr 08, 2005 at 03:32:56PM -0700, Maksim Yevmenkin wrote:
> hmm... why even use libusb? cant you just "fd = open("/dev/ugen0.1", 
> O_RDWR);" and then "write(fd, "MK255", 5)" and "read(fd, ...);". note: 
> here i assume ugen0 is the device.
> 
> >I'm also not entirely clear how/when to use usb_interrupt_read()
> >... as many of the commands listed in the manual return data, but
> >usb_inerrupt_write() doesn't seem to allow for data to be returned,
> >but following usb_interrupt_write(), the read will hang.
> 
> i'd guess you have to keep read pipe open at all times. that is what "fd 
> = open("/dev/ugen0.1", O_RDWR);" will do - it will open both read and 
> write pipes (because of O_RDWR).
> 
> then you just
> 
> write(fd, ...);
> read(fd, ...);

select(2) and non-blocking should work with ugen and interrupt endpoints
too.

-- 
B.Walter                   BWCT                http://www.bwct.de
bernd at bwct.de                                  info at bwct.de