SDK: Introduce fairmq error category

fairmq/sdk/Error.cxx

@@ -0,0 +1,40 @@
+/********************************************************************************
+ *    Copyright (C) 2019 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *              GNU Lesser General Public Licence (LGPL) version 3,             *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+
+#include "Error.h"
+
+namespace fair {
+namespace mq {
+
+const char* ErrorCategory::name() const noexcept
+{
+    return "fairmq";
+}
+
+std::string ErrorCategory::message(int ev) const
+{
+    switch (static_cast<ErrorCode>(ev)) {
+        case ErrorCode::OperationInProgress:
+            return "async operation already in progress";
+        case ErrorCode::OperationTimeout:
+            return "async operation timed out";
+        case ErrorCode::OperationCanceled:
+            return "async operation canceled";
+        case ErrorCode::DeviceChangeStateFailed:
+            return "failed to change state of a fairmq device";
+        default:
+            return "(unrecognized error)";
+    }
+}
+
+const ErrorCategory errorCategory{};
+
+std::error_code MakeErrorCode(ErrorCode e) { return {static_cast<int>(e), errorCategory}; }
+
+}   // namespace mq
+}   // namespace fair