确保C ++双精度是64位 [英] Ensuring C++ doubles are 64 bits

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位的浮点数。有没有一些方法来确保，在编译时，双精度是64位？是否还有其他类型，我应该用来存储数据？

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?

编辑：如果你正在阅读这个和实际上寻找一种方式

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

对于其他答案的改进假设一个字符是8位，标准不保证这一点。）。将是这样：

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< limits.h> 或< climits> 。

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