+#define USB_ERROR(s, x) do { if (x < 0) { fprintf(stderr, "usb %s: %s\n", s, usb_strerror(x)); usbtmc_clear(sc); return 0; } } while(0)
+
+/* Not in all libusb-1.0 versions, so we have to roll our own :-( */
+static char * usb_strerror(int e)
+{
+ static char unknerr[256];
+
+ switch (e) {
+ case LIBUSB_SUCCESS:
+ return "Success";
+ case LIBUSB_ERROR_IO:
+ return "Input/output error";
+ case LIBUSB_ERROR_INVALID_PARAM:
+ return "Invalid parameter";
+ case LIBUSB_ERROR_ACCESS:
+ return "Access denied (insufficient permissions)";
+ case LIBUSB_ERROR_NO_DEVICE:
+ return "No such device (it may have been disconnected)";
+ case LIBUSB_ERROR_NOT_FOUND:
+ return "Entity not found";
+ case LIBUSB_ERROR_BUSY:
+ return "Resource busy";
+ case LIBUSB_ERROR_TIMEOUT:
+ return "Operation timed out";
+ case LIBUSB_ERROR_OVERFLOW:
+ return "Overflow";
+ case LIBUSB_ERROR_PIPE:
+ return "Pipe error";
+ case LIBUSB_ERROR_INTERRUPTED:
+ return "System call interrupted (perhaps due to signal)";
+ case LIBUSB_ERROR_NO_MEM:
+ return "Insufficient memory";
+ case LIBUSB_ERROR_NOT_SUPPORTED:
+ return "Operation not supported or unimplemented on this platform";
+ case LIBUSB_ERROR_OTHER:
+ return "Other error";
+ };
+ snprintf(unknerr, sizeof(unknerr), "Unknown error code %d / 0x%02x", e, e);
+ return unknerr;
+}