Question

Edit: I posted the whole class (striped a few for the error irrelevant things out)

I made following class:

class packet
{public:char *  buffer;
    int     size;
    int     data;

    packet();
    packet(packet &text, int length=-1);
    packet(char * text, int length=-1);
    packet(int val);
    packet(char c);
    packet(double d);
    packet(float f);

    ~packet();

    packet &    operator=       (packet &text);
    packet      operator+       (packet &text);
    packet &    operator+=      (packet &text);
    packet &    operator|=      (packet &text);
    bool        operator==      (packet &text);
    bool        operator*=      (packet &text);
    bool        operator!=      (packet &text);

                operator char*  () const;
                operator int    () const;
                operator float  () const;
    char        operator []     (int pos)  const;
};

And I use the class like this:

    packet p = packet();

or

return packet();

And Visual Studio gives me this error:

test.cpp(162): error C2668: 'packet::packet' : ambiguous call to overloaded function
...packet.h(26): could be 'packet::packet(float)'
...packet.h(23): or       'packet::packet(int)'
...packet.h(22): or       'packet::packet(char *,int)'

Does anyone know what I am doing wrong here ? Why is this ambigous ?

PS: I think it has to do with the 4 operators at the bottom but I am a little hazy with overloading those kind of operators…

Solution: I got it working by marking some constructors as explicit:

class packet
{public:char *  buffer;
    int     size;
    int     data;

    packet();
    packet(packet &text, int length=-1);
    explicit packet(char * text, int length=-1);
    explicit packet(int val);
    explicit packet(char c);
    explicit packet(double d);
    explicit packet(float f);

    ~packet();

    packet &    operator=       (packet &text);
    packet      operator+       (packet &text);
    packet &    operator+=      (packet &text);
    packet &    operator|=      (packet &text);
    bool        operator==      (packet &text);
    bool        operator*=      (packet &text);
    bool        operator!=      (packet &text);

                operator char*  () const;
                operator int    () const;
                operator float  () const;
    char        operator []     (int pos)  const;
};

Answer 1

In case the error really occurs at the place where you try to assign the result of the function to a new variable, the problem could be your copy constructor. You should make the packet& in const so that it can be used with temporary objects:

packet(const packet & text, int length=-1);

The other constructors might come into play in this case if your class is implicitly convertible to int, float,….

Due to such issues it is usually advisable to not add unnecessary conversion operators and mark constructors as explicit to avoid unexpected implicit conversions.