无法在C#中将关键字“固定"用于变量 [英] Can't use keyword 'fixed' for a variable in C#

问题描述

我用数组和字符串变量对关键字 fixed 进行了测试，效果很好，但是我不能使用单个变量.

I tested the keyword fixed with array and string variables and worked really well but I can't use with a single variable.

static void Main() {

    int value = 12345;
    unsafe {
        fixed (int* pValue = &value) { // problem here
            *pValue = 54321;
        }
    }
}

固定的行(int * pValue =& value)会导致编译器错误.我不明白，因为变量 value 不在 unsafe 块之外，并且尚未固定.

The line fixed (int* pValue = &value) causes a complier error. I don't get it because the variable value is out of the unsafe block and it is not pinned yet.

为什么不能对变量 value 使用 fixed ?

Why can't I use fixed for the variable value?

推荐答案

这是因为 value 是在堆栈上分配的局部变量，因此它已经固定.错误消息中提到了这一点:

This is because value is a local variable, allocated on the stack, so it's already fixed. This is mentioned in the error message:

CS0213您不能使用fixed语句获取已经固定的表达式的地址

CS0213 You cannot use the fixed statement to take the address of an already fixed expression

如果您需要 value 的地址，则不需要 fixed 语句，则可以直接获取它:

If you need the address of value, you don't need the fixed statement, you can get it directly:

int* pValue = &value;

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