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c++syntaxconstructorpimpl-idiom

Strange "type class::method() : stuff " syntax C++

While reading some stuff on the pImpl idiom I found something like this:

MyClass::MyClass() : pimpl_( new MyClassImp() )

First: What does it mean?
Second: What is the syntax?
Sorry for being such a noob.

Solution

  • This defines the constructor for MyClass.

    The syntax is that of a constructor definition with an initialization list (I assume there is a set of braces following this that define the body of the constructor).

    The member pimpl_ of MyClass is being initialized as a pointer to a new object of type MyClassImp. It's almost the same as the following:

    MyClass::MyClass()
{
    pimpl_ = new MyClassImp();
}

    However, it is preferable to use the initialization list for initializing class members wherever possible; see the C++ FAQ Lite entry linked above.