c++ Overload a virtual function

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I try to extend the Arduino IDE for ARM based boards with 9bit support for the Serial connections, but i can't get the function overloading right. I have read as many post here on SO as well as on the internet on overloading, overriding and hiding but everything i try fails with compiler errors. Hopefully anybody can explain what i need to do to achieve my goal.

Note: The Classes below show only the interesting parts.

It all begins in the Print.h:

    class Print
    {
    public:
      virtual size_t write(uint8_t) = 0;
      size_t write(const char *str) {
        if (str == NULL) return 0;
        return write((const uint8_t *)str, strlen(str));
      }   
      virtual size_t write(const uint8_t *buffer, size_t size);
      size_t write(const char *buffer, size_t size) {
        return write((const uint8_t *)buffer, size);
      }
    }

Then Stream inherits from Print (but no changes to write).

In HardwareSerial.h HardwareSerial inherits from Stream:

    class HardwareSerial : public Stream
    {
    public:
      virtual size_t write(uint8_t) = 0;
      using Print::write; // pull in write(str) and write(buf, size) from Print
    }

And finally in USARTClass.h inherits USARTClass from HardwareSerial:

    class USARTClass : public HardwareSerial
    {
    public:
      size_t write( const uint8_t c ) ; 
    }

In USARTClass.cpp the write method is implemented. I want to override the write function with one that takes a uint16_t as argument:

    class USARTClass : public HardwareSerial
    {
    public:
      size_t write( const uint8_t c ) ; 
      size_t write( const uint16_t c ) ;
    }

If i do so i always get a compiler error:

    error: call of overloaded 'write(int)' is ambiguous
    note: candidates are:
    USARTClass.h:89:12: note: virtual size_t USARTClass::write(uint8_t)
        size_t write( uint8_t ) ;
               ^
    USARTClass.h:90:12: note: size_t USARTClass::write(uint16_t)
        size_t write( uint16_t ); 
               ^
    Print.h:49:12: note: size_t Print::write(const char*) <near match>
        size_t write(const char *str) {
               ^
    Print.h:49:12: note:   no known conversion for argument 1 from 'int' to 'const char*'

I simply don't understand what i have to do to overload the write method.

asked 45 secs ago

Bouni

13

c++ Overload a virtual function