如何在C中定义函数数组 [英] How to define an array of functions in C

问题描述

我有一个包含如下声明的结构:

I have a struct that contains a declaration like this one:

void (*functions[256])(void) //Array of 256 functions without arguments and return value

在另一个函数中我想定义它，但是有 256 个函数！我可以这样做:

And in another function I want to define it, but there are 256 functions! I could do something like this:

struct.functions[0] = function0;
struct.functions[1] = function1;
struct.functions[2] = function2;

等等，但是这太累了，我的问题是有什么方法可以做这样的事情吗?

And so on, but this is too tiring, my question is there some way to do something like this?

struct.functions = { function0, function1, function2, function3, ..., };

编辑:如 Chris Lutz 所说，语法错误已更正.

EDIT: Syntax error corrected as said by Chris Lutz.

推荐答案

我有一个包含如下声明的结构:

I have a struct that contains a declaration like this one:

不，你没有.那是语法错误.您正在寻找:

No you don't. That's a syntax error. You're looking for:

void (*functions[256])();

这是一个函数指针数组.但是请注意，void func() 不是不带参数且不返回任何内容的函数".它是一个函数，它接受未指定的数字或类型的参数并且不返回任何内容.如果你想要没有参数"，你需要这个:

Which is an array of function pointers. Note, however, that void func() isn't a "function that takes no arguments and returns nothing." It is a function that takes unspecified numbers or types of arguments and returns nothing. If you want "no arguments" you need this:

void (*functions[256])(void);

在 C++ 中，void func() 确实 的意思是不带参数"，这会引起一些混淆(尤其是因为 C 为 void func() 指定的功能) 的价值可疑.)

In C++, void func() does mean "takes no arguments," which causes some confusion (especially since the functionality C specifies for void func() is of dubious value.)

无论哪种方式，您都应该 typedef 您的函数指针.这将使代码更容易理解，并且您只有一次机会(在 typedef 处)弄错语法:

Either way, you should typedef your function pointer. It'll make the code infinitely easier to understand, and you'll only have one chance (at the typedef) to get the syntax wrong:

typedef void (*func_type)(void);
// ...
func_type functions[256];

反正你不能赋值给一个数组，但是你可以初始化一个数组并复制数据:

Anyway, you can't assign to an array, but you can initialize an array and copy the data:

static func_type functions[256] = { /* initializer */ };
memcpy(mystruct.functions, functions, sizeof(functions));

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