在C＃中布尔*实用性 [英] Usefulness of bool* in C#

问题描述

我可以在任何一种有意义的方式使用 BOOL * 。我将如何转换 BOOL * 到字节例如，或者存储 BOOL * 在一个字节

Can I use bool* in any kind of meaningful way. How would I convert bool* to a byte for instance, or store bool* in a byte

我的目标是管理我的项目我的记忆中，具体细节并不重要，只是一些ID喜欢做的事。现在，我想是能够存储我自己的变量，我碰巧需要存储一个布尔值。我如何使用不安全和字节* ，保存这个布尔值，并利用我的空间最好？理想的情况下，以4位存储字节。

My goal is to manage my own memory in a project of mine, the specifics aren't important, just something id like to do. Now I would like to be able to store my own variables, and i happen to need to store a boolean value. How can i, using unsafe and a byte*, store this boolean value, and utilize my space best? Ideally to store 4 bits in the byte.

推荐答案

在C＃中，你一般不会使用 BOOL * ，这是一件好事，你只能使用不安全code（这带来了一大堆其他东西一样钉住对象等等）。 A BOOL * 将是一个指向一个布尔值。指针是4字节长，并且不能被转换为一个字节，而不损失

In C# you wouldn't normally use a bool*, which is something you can only use in unsafe code (which brings forth a whole lot of other stuff like pinning objects and so forth). A bool* would be a pointer to a boolean. A pointer is 4 bytes long and cannot be converted to a byte without loss.

为什么要做到这一点，你会遇到这样的在哪里？通常情况下，有不容易用例在C＃中使用指针，除非你有一个非常明确的要求（即API调用，但可以解决使用P / Invoke）。

Why would you want to do this and where do you encounter this? Normally, there's not easily a use case for using pointers in C# unless you have a very specific demand (i.e., an API call, but that you can solve using P/Invoke).

编辑：（因为你编辑你的Q）

(because you edited your q.)

以下code段显示如何获得布尔变量的地址，以及如何为该指针转换为 INT （转换为字节是不可能的，我们需要四个字节）。

The following code snippet shows you how to get the address of a boolean variable and how to convert that pointer to an int (converting to byte is not possible, we need four bytes).

unsafe
{
    // get pointer to boolean
    bool* boolptr = &mybool;                

    // get the int ptr (not necessary though, but makes following easier)
    int* intptr = (int*)boolptr;

    // get value the pointer is pointing at
    int myint = *intptr;

    // get the address as a normal integer
    int myptraddress = (int) intptr;
}

您说的理想商店4字节位。除非你有一个4位的机器架构，我强烈反对意见，因为它会使检索和存储的布尔值很慢。但更重要的是：你在这里谈论C＃，而不是C ++。 C＃势必其中指出一个布尔被存储为字节，并且每个存储器地址是长在32位体系结构，这意味着指针是四个字节长四个字节的CLR。因此，你的问题，一个bool *转换（指针布尔）别的东西只能转换为整数或其他数据类型，它是宽4个字节。

you say "ideally store 4 bits in a byte". Unless you have a 4-bits machine architecture, I'd strongly advice against it because it will make retrieving and storing the booleans very slow. But more importantly: you are talking C# here, not C++. C# is bound to the CLR which states that a boolean is stored as a byte and that each memory address is four bytes long in 32 bits architectures, which means pointers are four bytes long. Hence, your question, converting a bool* (pointer to a bool) to something else can only be converted into an integer or other datatype that is four bytes wide.

一个技巧：使用标志可以最好地利用空间：这使枚举类型占用一点对于每个标志，它给你八布尔每个字节

A tip: using flags you can utilize space best: this makes enum types take up a bit for each flag, which gives you eight booleans for each byte.

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