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Asked: 2026-05-24T22:24:19+00:00

I had trouble with initializing arrays of pointers. What I found out compiling with

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I had trouble with initializing arrays of pointers. What I found out compiling with gcc c++ (4.6.0) is:

MyClass** a = new MyClass*[100];

Does not always initalize the array of pointers. (most of the time it did give me an array of null pointers which confused me)

MyClass** a = new MyClass*[100]();

DOES initialize all the pointers in the array to 0 (null pointer).

The code I’m writing is meant to be be portable across Windows/Linux/Mac/BSD platforms. Is this a special feature of the gcc c++ compiler? or is it standard C++? Where in the standard does it says so?

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  1. Editorial Team

    This value-initialization is standard C++.

    The relevant standardeese is in C++98 and C++03 §5.3.4/15. In C++98 it was default-initialization, in C++03 and later it’s value initialization. For your pointers they both reduce to zero-initialization.

    C++03 §5.3.4/15:

    – If the new-initializer is of the form (), the item is value-initialized (8.5);

    In C++0x that paragraph instead refers to “the initialization rules of 8.5 for direct-initialization”, where in N3290 (the FDIS) you find about the same wording in §8.5/16.

    Cheers & hth.,

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