Should I explicitly zero initialize auto_ptr?

Question

Some of my colleagues prefer to explicitly initialize std::auto_ptr to 0 in constructor initialization list, but it will be initialized to 0 in it's constructor without any explicit initialization. So is there any reason to do it?

#include <memory>

class A
{
  A() : SomePtr(0)
  {
  }

private:
  std::auto_ptr<SomeType> SomePtr;
};

possible duplicate of [Is there any need to assign null pointer to std::auto_ptr](http://stackoverflow.com/questions/3664145/is-there-any-need-to-assign-null-pointer-to-stdauto-ptr) — Alex B, Oct 06 '11 at 09:24

score 9 · Accepted Answer · answered Oct 06 '11 at 09:23

9

No, the default constructor of std::auto_ptr does exactly that, so doing it explicitly is not necessary. In any case, it's a matter of style and you should be consistent. For instance, would you explicitly call the default constructor of a member vector in the constructor initialization list?

As a side note, std::auto_ptr is deprecated in the upcoming standard

answered Oct 06 '11 at 09:23

Armen Tsirunyan

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The "upcoming" standard has happened, it's now the "latest" standard! Hoorah, and cheering! Granted, it hasn't been *implemented* yet. – Steve Jessop Oct 06 '11 at 09:28
Ok, the only reason is style and consistency. – ks1322 Oct 06 '11 at 09:44

score 0 · Answer 2 · answered Oct 06 '11 at 09:27

Psychology.

For built-in types, you probably already know they are uninitialized unless you do so explicitly. For classes, this is not the case.

A strive to consistency results in explicit initialization everywhere. This allows you to forget if A::SomePtr is a built-in or a class type. Pretty useless, imho, since the amount of built-in types is quite limited.

score 0 · Answer 3 · answered Oct 06 '11 at 09:28

One reason maybe clarity, but that should be the only one. I myself prefer not to write unneccessary intialization, especially if that completely spares me from writing a default constructor for the surrounding class and just let the compiler do its job. Whereas it's merely a matter of style, I think too much over-paranoia does even harm the clarity of the code.

Should I explicitly zero initialize auto_ptr?

3 Answers3