Is it possible to have constructor have different name as the class declared?

Question

I have a quick question while reading a source code. AFAIK, the name of a constructor should be identical to the class declared. But, the following code has a different name as a constructor. Anybody can tell me why this code works?

class directFieldMapper
:
    public FieldMapper
{
    const labelUList& directAddressing_;

    bool hasUnmapped_;

public:

    // Constructors

        //- Construct given addressing
        patchFieldSubset(const labelUList& directAddressing)
        :
            directAddressing_(directAddressing),
            hasUnmapped_(false)
        {
            if (directAddressing_.size() && min(directAddressing_) < 0)
            {
                hasUnmapped_ = true;
            }
        }

    //- Destructor
    virtual ~directFieldMapper()
    {}
}

Ok, I found that this class is not in the source code list in the Makefile. So, this class is never compiled.

patchFieldSubset is not a constructor for directFieldMapper. — user2672107
– user2672107, Commented Feb 6, 2018 at 16:41
"why this code works?" this code does not work, at least as shown here there will be a couple of compiler errors unrelated to the actual issue. Can you provide a minimal reproducible example? — 463035818_is_not_an_ai
– 463035818_is_not_an_ai, Commented Feb 6, 2018 at 16:44
Could patchFieldSubset be a nested class inside directFieldMapper, and you just missed/accidentally omitted the relevant code? Indentation suggests that that could be possible. — Sergey Kalinichenko
– Sergey Kalinichenko, Commented Feb 6, 2018 at 16:45

eerorika · Accepted Answer · 2018-02-06 16:54:53Z

5

Is it possible to have constructor have different name as the class declared?

No.

AFAIK, the name of a constructor should be identical to the class declared.

Correct.

But, the following code has a different name as a constructor.

The code is ill-formed according to C++ standard.

Anybody can tell me why this code works?

If it works, then it is due to some language extension. You can consult the manual of your compiler about language extensions it provides, and how to enable / disable them.

Being ill-formed, all compilers are required to issue a diagnostic message, or else they are not compliant. Example output from the GNU compiler:

error: ISO C++ forbids declaration of 'patchFieldSubset' with no type [-fpermissive]

         patchFieldSubset(const labelUList& directAddressing)

                                                            ^

warning: non-static reference 'const labelUList& directFieldMapper::directAddressing_' in class without a constructor [-Wuninitialized]

     const labelUList& directAddressing_;

                       ^~~~~~~~~~~~~~~~~

error: expected ';' after class definition

 }
  ^

edited Feb 6, 2018 at 16:54

answered Feb 6, 2018 at 16:46

eerorika

240k13 gold badges212 silver badges354 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

skypjack Over a year ago

I would mention that constructors cannot have different names because constructors have no names at all, accordingly with the standard.

Collectives™ on Stack Overflow

Is it possible to have constructor have different name as the class declared?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related