added source file OpalRT.cc (accidentally omitted in prior commit)

src/comm/OpalRT.cc

+#include "OpalRT.h"
+
+namespace OpalRT
+{
+    //    lastErrorMsg = QString();
+    void OpalErrorMsg::displayLastErrorMsg()
+    {
+        static QString lastErrorMsg;
+        setLastErrorMsg();
+        QMessageBox msgBox;
+        msgBox.setIcon(QMessageBox::Critical);
+        msgBox.setText(lastErrorMsg);
+        msgBox.exec();
+    }
+
+    void OpalErrorMsg::setLastErrorMsg()
+    {
+        char* buf = new char[512];
+        unsigned short len;
+        static QString lastErrorMsg;
+        OpalGetLastErrMsg(buf, sizeof(buf), &len);
+        lastErrorMsg.clear();
+        lastErrorMsg.append(buf);
+        delete buf;
+    }
+}