如何检查类型正确的类型指针？ [英] How do I check a typed pointer is properly aligned for that type?

问题描述

假设我有一个模板化函数，处理指向未知类型 T 的指针。现在，如果在64位平台上类型 T 恰好是 void * ，则它必须是8字节对齐的，但是如果 T 恰好是 char ，则必须对齐1个字节，并且 T 恰好是一个类，因此其对齐要求将取决于其成员变量。

Suppose I have a templated function that deals with pointers to yet unknown type T. Now if type T happens to be void* on 64-bit platform then it must be 8-bytes aligned, but if T happens to be char it must be 1-byte aligned and if T happens to be a class then its alignment requirements will depend on its member variables.

所有这些都可以在纸上进行计算，但是我如何使编译器产生给定类型 T 的对齐要求吗？

This all can be computed on paper, but how do I make the compiler yield the alignment requirements for a given type T?

有没有办法在编译时找到对齐方式

Is there a way to find during compile time the alignment requirements for a given type?

推荐答案

在C ++ 11中，您可以使用 alignof 和 alignas 进行断言并提供对齐要求。另请参阅 std :: align 以控制运行时的对齐方式。

In C++11 you can use alignof and alignas to make asserts and provide requirements for alignment. Also look at std::align to control alignment in runtime.

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