The user can't be bothered with the cumbersome #ifdef logic, rather directly instead the SerialDispatcher within the library and make it available via extern declaration.

Author: aentinger

src/io/serial/SerialDispatcher.cpp

@@ -332,3 +332,19 @@ void SerialDispatcher::handleSerialReader()
                   });
   }
 }
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include <Arduino.h>
+
+/**************************************************************************************
+ * GLOBAL VARIABLE DECLARATION
+ **************************************************************************************/
+
+#ifdef ARDUINO_PORTENTA_H7_M4
+  SerialDispatcher Serial(Serial1); /* No SerialUSB for Portenta H7 / M4 Core */
+#else
+  SerialDispatcher Serial(SerialUSB);
+#endif

src/io/serial/SerialDispatcher.h

@@ -102,4 +102,11 @@ class SerialDispatcher : public arduino::HardwareSerial
   void handleSerialReader();
 };
 
+/**************************************************************************************
+ * EXTERN DECLARATION
+ **************************************************************************************/
+
+#undef Serial
+extern SerialDispatcher Serial;
+
 #endif /* SERIAL_DISPATCHER_H_ */