Print version number of device 1 on each raw dev.

Only works on HID++ >=2.0 so far. Also solves a race condition where
the wrong response can be sent to a request.

src/logid/backend/hidpp20/Error.cpp

@@ -0,0 +1,46 @@
+#include <cassert>
+#include <cstring>
+#include "Error.h"
+
+using namespace logid::backend::hidpp20;
+
+Error::Error(uint8_t code) : _code (code)
+{
+    assert(_code != NoError);
+}
+
+const char* Error::what() const noexcept
+{
+    switch(_code)
+    {
+        case NoError:
+            return "No error";
+        case Unknown:
+            return "Unknown";
+        case InvalidArgument:
+            return "Invalid argument";
+        case OutOfRange:
+            return "Out of range";
+        case HardwareError:
+            return "Hardware error";
+        case LogitechInternal:
+            return "Logitech internal feature";
+        case InvalidFeatureIndex:
+            return "Invalid feature index";
+        case InvalidFunctionID:
+            return "Invalid function ID";
+        case Busy:
+            return "Busy";
+        case Unsupported:
+            return "Unsupported";
+        case UnknownDevice:
+            return "Unknown device";
+        default:
+            return std::string("Unknown error code " + std::to_string(_code)).c_str();
+    }
+}
+
+uint8_t Error::code() const noexcept
+{
+    return _code;
+}