Re: [Libusb-devel] usb_interrupt_read error

[Johannes E. <joh...@er...>]

That's a bug in the current code which happens when a timeout occurs.

The code doesn't do any signal handling right now.

Are you expecting data to be delivered within 10 seconds (from looking
at the call to usb_interrupt_read)?

JE

On Tue, May 06, 2003, Derek Hansen <de...@wi...> wrote:
> I am trying to do an interrupt transfer from a device. I'm using the
> usb_interrupt_read() method.  When the method runs it prints "Alarm clock"
> to the screen and my program terminates. What could be causing this error
> and how can I remedy it?
> 
> Here is a cutting of my code:
> 
> struct usb_bus *bus;
>     struct usb_device *dev;
>     struct usb_dev_handle * handle;
> 
>     int stat;
>     int interfaceNum;
>     int altNum;
>     int endPoint;
>     int numBytes;
>     int quit;
> 
>     char buf[2048];
> 
>     usb_init();
> 
>     usb_find_busses();
>     usb_find_devices();
> 
>     for (bus=usb_get_busses(); bus; bus = bus->next) {
>      for (dev = bus->devices; dev; dev = dev->next) {
>       if ((dev->descriptor.idVendor == 0x0c2e)&&(dev->descriptor.idProduct
> == 0x0700)) {
>        printf("*****Found the metrologic scanner*****\n");
>        break;
>       }
>      }
>     }
> 
>     handle = usb_open(dev);
> 
>   stat = usb_set_configuration( handle,
> dev->config[0].bConfigurationValue );
> 
>   interfaceNum = dev->config[0].interface[0].altsetting[0].bInterfaceNumber;
>   stat = usb_claim_interface(handle, interfaceNum);
> 
>   altNum = dev->config[0].interface[0].altsetting[0].bAlternateSetting;
>   stat = usb_set_altinterface(handle, altNum);
> 
>   quit = 0;
>   while ( !quit ) {
>    printf("Reading from scanner\n");
> 
>        endPoint
> =dev->config[0].interface[0].altsetting[0].endpoint[1].bEndpointAddress;
>        numBytes
> =dev->config[0].interface[0].altsetting[0].endpoint[1].wMaxPacketSize;
> 
>        printf("%d =ep, %d = bytes\n" ,endPoint, numBytes);
> 
>        stat = usb_interrupt_read( handle, endPoint, buf, numBytes, 10000 );
> 
>        printf("Read: %s\n",buf);
> 
>        if ( stat<0 ) {
>     quit = 1;
>        }
>   }
> 
>