[Libusb-win32-devel] Problem with one libusb program interfering with another

[Graeme G. <gr...@ar...>]

[Thanks for the help withe getting the driver working. It seems
  to compile and install OK now.]

I've noticed a strange thing using libusb-win32. If I've
got one program happily communicating with my device,
and I start another instance of the program, just scanning
though the available USB devices. ie.

     usb_init();
     usb_find_busses();
     usb_find_devices();

     for (bus = usb_get_busses(); bus != NULL; bus = bus->next) {
         struct usb_device *dev;
         for (dev = bus->devices; dev != NULL; dev = dev->next) {
             ... examine dev structure ...
         }
     }

then not only does the second instance suffer a substantial
delay before it completes these operations, but the first
programs communications get completely fouled up - in fact,
the communications stop, and it's necessary to unplug and replug
the device to get things going again.

(This is true if testlibusb.exe is substituted for the second instance
  of my program, since it essentially does the same sort of things.)

Is this expected behaviour ? What is the cause ? How can it be avoided ?

thanks,
	Graeme Gill.