本文有xhz1234（徐洪志）编写，转载请注明出处。

http://blog.csdn.net/xhz1234/article/details/36635083

作者：徐洪志 

近期阅读Linux-内核代码。发现非常多地方使用了函数指针，遂自己写一个演示样例程序。以供參阅：

#include <stdlib.h>
#include <stdio.h>

#define ADDONE 0
#define MINUSONE 1
#define S_OK 0
#define S_ERR -1

typedef int(*dir_fn)(int *data); //函数指针

//实际函数1
int add_func(int *data)
{
	(*data)++;
	return S_OK;
}

//实际函数2
int minus_func(int *data)
{
	(*data)--;
	return S_OK;
}

//核心：依据參数cmd，获取相应的func
dir_fn lookup_ctl(int cmd)
{
	dir_fn fn = NULL;
	switch(cmd)
	{
		case ADDONE:
			fn = add_func;
			break;
		case MINUSONE:
			fn = minus_func;
			break;
		default:
			break;
	}

	return fn;
}


int main(void)
{
	int data = http://www.mamicode.com/100;	"Input the cmd<0 add, 1 minus>\n");
	scanf("%d", &cmd);

	fn = lookup_ctl(cmd);
	
	fn(&data);
	
	printf("Result is: %d\n", data);

	return 0;
}