是什么`（（无效（*）（））为0x1000）（）;'是什么意思？ [英] What does `((void (*)())0x1000)();` mean?

问题描述

下面是一个code，它的目的是设定程序计数器跳转到地址 0×1000 。我知道它做什么，但我不明白。它关系到我缺乏的C语言知识。可能是你能赐教。下面是声明/功能（我甚至不知道它是什么：））

Here is a code that purpose is to set the program counter to jump to address 0x1000. I know what it does but I don't understand how. It is related to my lack of C language knowledge. May be you can enlighten me. Here is the statement/function (I even don't know what it is :))

((void (*)())0x1000)();

我的事情是指针，返回无效和不接受任何参数的函数。如果我错了，请大家指正。

I thing it is pointer to a functions that returns void and accepts no argument. Please correct me if I am wrong.

推荐答案

C 声明是由内德$ C $光盘拿出来用一个简单的规则：从标识符开始和右侧检查 [] （阵列）或（）（功能），然后检查左侧为值（存储阵列中或由函数返回），不越位括号的类型;从括号逃脱，并重复。

C declarations are decoded from inside out using a simple rule: start from the identifier and check on the right side for [] (array) or () (function) then check on the left side for the type of the values (stored in the array or returned by the function), without crossing the parentheses; escape from the parentheses and repeat.

例如：

void (*p)()

P 是（右侧无）的指针的（在左边，不要过括号中）的到的（逃避括号，看了下一级）的函数的（右）的不返回任何内容的（左）。

p is (nothing on the right) a pointer (on the left, don't cross the parentheses) to (escape the parentheses, read the next level) a function (right) that returns nothing (left).

在剩下的标识符（ P 在这种情况下）丢失，都是一个类型声明。

When the identifier (p in this case) is missing, all that remains is a type declaration.

括号括起A型，把一个价值面前的是一个类型转换。

A type enclosed in parentheses, put in front of a value is a type cast.

(void (*)())0x1000

转换次数 0×1000 到指针，不会对该款返回任何的（见什么是括号外的函数 p 的声明之上）。

converts the number 0x1000 to a pointer to a function that doesn't return anything (see what's outside the parentheses in the paragraph about the declaration of p above).

在下一级别，前pression上述（一个指针指向一个功能可以以相同的方式作为函数名中使用）被用于执行code对准

On the next level, the expression above (a pointer to a function can be used in the same way as a function name) is used to execute the code pointed at.

请参见下面的整个前pression去组成：

See below the entire expression de-composed:

(
  (
    void (*)()   /* type: pointer to function that doesn't return anything     */
  )0x1000        /* value 0x1000 treated as a value of the type declared above */
)                /* enclose in parentheses to specify the order of evaluation  */ 
();              /* the pointer above used as a function name to run the code  */

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