确保 C++ 双精度为 64 位

Ensuring C++ doubles are 64 bits(确保 C++ 双精度为 64 位)

问题描述

在我的 C++ 程序中，我需要从外部字节序列中提取一个 64 位浮点数.有没有办法在编译时确保双打是 64 位?我应该使用其他类型来存储数据吗?

In my C++ program, I need to pull a 64 bit float from an external byte sequence. Is there some way to ensure, at compile-time, that doubles are 64 bits? Is there some other type I should use to store the data instead?

如果您正在阅读本文并且实际上正在寻找一种确保以 IEEE 754 格式存储的方法，请查看下面的 Adam Rosenfield 的回答.

If you're reading this and actually looking for a way to ensure storage in the IEEE 754 format, have a look at Adam Rosenfield's answer below.

推荐答案

对其他答案的改进(假设 char 是 8 位，标准不保证这一点......).应该是这样的:

An improvement on the other answers (which assume a char is 8-bits, the standard does not guarantee this..). Would be like this:

char a[sizeof(double) * CHAR_BIT == 64];

或

BOOST_STATIC_ASSERT(sizeof(double) * CHAR_BIT == 64);

您可以在 或 中找到定义的 CHAR_BIT.

You can find CHAR_BIT defined in <limits.h> or <climits>.

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