Returning *this in member functions

Question

I recently used a library that allows the following type of syntax:

MyClass myObject;
myObject
    .setMember1(\"string value\")
    .setMember2(4.0f)
    .s         


        

Answer 1

This is sometimes referred to as the Named Parameter Idiom or method chaining. This isn't bad practice, it can aid readability. Consider this example lifted from the C++ FAQ

File f = OpenFile("foo.txt")
            .readonly()
            .createIfNotExist()
            .appendWhenWriting()
            .blockSize(1024)
            .unbuffered()
            .exclusiveAccess();

The alternative would be to use positional arguments to the OpenFile method, requiring the programmer to remember the position of each argument.