Is it inheritance for functions or something else?

Question

What does the following C++ syntax mean?

my_s_module::my_s_module(mylib::cont const& c)
    :mylib::s_module{c}
{
    // Some content;
}

It looks like inheritance to me. But I know that for inheritance the syntax is a follows:

class Child: public Parent
{
}

And in the first example we have something like that:

Child(some_type const& x): public Parent{x}
{
}

So, I do not know what it means. Could anybody please explain me this syntax?

ADDED

I probably need to add, that in the comments to this code it is written that it is "Constructor of the module". But what does it mean? I know what a constructor of a class mean but what is a constructor of a module?

All of the answers below have should have given you a good sense of what this code does, but to answer you specifically: in this scope it seems that the word module and class are the same thing. this code snippet has nothing to do with inheritance, your confusion stems from the use of the colon: here it is used to initialize members of the class during construction. — NiRR, Aug 12 '13 at 12:45

cpp · Answer 1 · 2013-08-12T12:36:13.570

0

This is a constructor of class my_s_module defined outside the class definition. This constructor initializes a member s_module of a nested class mylib to c, which is the argument of the constructor.

edited Aug 12 '13 at 12:36

answered Aug 12 '13 at 12:31

cpp

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score 0 · Answer 2 · answered Aug 12 '13 at 12:32

0

From your description, it's just an initialisation list in a constructor.

After the colon, you specify the class members and initial values for them.

For example: http://www.learncpp.com/cpp-tutorial/101-constructor-initialization-lists/

answered Aug 12 '13 at 12:32

Karadur

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score 0 · Answer 3 · answered Aug 12 '13 at 12:35

It's a regular initialization list in the constructor of the class my_s_module, which inherits from s_module, which is in the namespace (or class) mylib.

The code should look something like this:

namespace mylib
{ 
    class cont
    {
       // ...
    };

    class s_module
    {
    public:
        s_module(cont const&);
        // ...
    };
}

class my_s_module : public mylib::s_module
{
public:
    my_s_module(mylib::cont const &);
};

// Constructor implementation
my_s_module::my_s_module(mylib::cont const& c)
    : mylib::s_module{c}  // Initialize the base class. The {} around the argument is a C++11 feature.
{
    // Some content;
}

Is it inheritance for functions or something else?

3 Answers3