String constructor bug

The following code outputs “13” rather than “D”

unsigned long test = 13;
String thisString = String(test, HEX);

The string constructors that take a base as the second argument do not appear to work as intended for unsigned long or unsigned int values.

You are right. This is code from Arduino 0022

String::String( const unsigned long value, const int base )
  char buf[33];   
  ultoa(value, buf, 10);
  getBuffer( _length = strlen(buf) );
  if ( _buffer != NULL )
    strcpy( _buffer, buf );


ultoa(value, buf, 10);

Should be

ultoa(value, buf, base);

But to be honest, I don't think the String class should be constructible from integers anyway, especially since the constructors aren't declared as 'explicit'.

Code from WString.h

    String( const int, const int base=10);
    String( const unsigned int, const int base=10 );
    String( const long, const int base=10 );
    String( const unsigned long, const int base=10 );

This allows for implicit type conversion from an integer to a string:

String s;

// This can be confusing, making programmers
// think s is an integer. The integer 100 is converted 
// to a String and then assigned to the variables s.
s = 100;

// The same thing happens with functions.
void foo(String s)
\\ ...

// The integer 100 is implicitly converted to a String.

// The function call foo(100) is the same as


That was very helpful! I came across this bug today. So, is it possible to correct it? Is there a file a can change? Could you please explain the procedure? Thanks

C:\Program Files (x86)\arduino-0022\hardware\arduino\cores\arduino\Wstring.cpp line 91

reported it at - -