C ++：新的调用，像calloc一样？ [英] C++: new call that behaves like calloc?

问题描述

是否可以调用 new 让它清空内存，如 calloc ？

Is there a call I can make to new to have it zero out memory like calloc?

推荐答案

与他们的答案中有些人说的相反，是可能的。

Contrary what some are saying in their answers, it is possible.

char * c = new char[N]();

将零初始化所有字符（实际上，它被称为值初始化，但值初始化将对标量类型数组的所有其成员进行零初始化）。如果这是你的后。

Will zero initialize all the characters (in reality, it's called value-initialization. But value-initialization is going to be zero-initialization for all its members of an array of scalar type). If that's what you are after.

值得注意的是，它也适用于没有用户声明构造函数的类类型数组，在这种情况下，它们的任何成员都是值初始化的：

Worth to note that it does also work for (arrays of) class-types without user declared constructor in which case any member of them is value initialized:

struct T { int a; };
T *t = new T[1]();
assert(t[0].a == 0);
delete[] t;

这不是一些扩展或东西。它的工作和行为方式在C ++ 98中也是一样。只是在那里它被称为默认初始化而不是值初始化。然而，在标量或标量或POD类型的数组的两种情况下都进行零初始化。

It's not some extension or something. It worked and behaved the same way in C++98 too. Just there it was called default initialization instead of value initialization. Zero initialization, however, is done in both cases for scalars or arrays of scalar or POD types.

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