Add callback, callback doesnt fire

hanvon-libusb.c

@@ -65,16 +65,21 @@ struct hanvon {
 	char phys[32];
 };
 
-
+void callback(struct libusb_transfer *transfer) {
+  int i = 0;
+  for(; i < 10; i++) {
+    printf("%c, ", transfer -> buffer[i]);
+  }
+  printf("placeholder\n");
+}
 
 libusb_device *FindHanvon( libusb_context **context);
 int HandleData( void );
 
 
-
 int main()
 {
-  libusb_context **context;
+  libusb_context *context;
   libusb_device *device;
   libusb_device_handle *handle;
 
@@ -82,7 +87,7 @@ int main()
   if( state != STATE_SUCCESS )
     return state;
 
-  device = FindHanvon( context );
+  device = FindHanvon(& context );
   if( device == NULL )
     return STATE_NOT_FOUND;
 
@@ -92,7 +97,28 @@ int main()
 
 
   // Wait and handle interrupts?
+  struct libusb_transfer tx;
   
+  const int ENDPOINT_ADDR = 0x81; // bEndpointAddress from lsusb -v
+  const unsigned int LEN = 10;    // wMaxPacketSize from lsusb -v
+  unsigned char buffer[LEN];
+  // assign timeout of 1s, for any action is too much as is
+  libusb_fill_interrupt_transfer(&tx, 
+                                 handle, 
+                                 ENDPOINT_ADDR, 
+                                 buffer, 
+                                 LEN,
+                                 callback,
+                                 NULL, 
+                                 130); // milliseconds
+
+  state = libusb_submit_transfer(&tx);
+  if( state != STATE_SUCCESS )
+    return state;
+
+  for(;;) {
+    libusb_handle_events(context);
+  }
   return state;
 }