Declaring a template-class object: Error: no matching function for call to

Question

When I try to build my project, I get the error message " error: no matching function for call to 'Ringbuffer<void*>::Ringbuffer()' ". This is the code that doesn't work, and I wonder why C++ even tries to call " Ringbuffer() " since I only want to declare an object in Producer . The constructor of Ringbuffer takes three arguments. Has anyone an idea? Thanks a lot!

#include "Ringbuffer.h"
    
class Producer{
    private:

    Ringbuffer<void*> rbuf;
public:
    Producer();
};

Producer::Producer(){

}

Answer 1

why C++ even tries to call "Ringbuffer()"

Because rbuf is a member of Producer and when you construct a Producer that member is constructed as well. If you don't do it explicitly, then rbuf is implicilty default constructed.

The constructor of Ringbuffer takes three arguments.

When Ringbuffer has no default constructor (one that can be called without parameter) but only one with 3 arguments, then it cannot be default constructed.

Has anyone an idea?

Call the constructor:

Producer::Producer() : rdbuf(foo,bar,baz)  {

}

where foo , bar and baz are the parameters you want to use to construct the Ringbuffer .