int*(*)(int*,int*(*)())的类型

Question

int*(*)(int*,int*(*)())

我想知道它是什么类型的？,有人可以举例说明使用此类型的声明.

任何帮助都会很棒.

谢谢.

Answer 1

它是一个指向函数的指针,它返回int*并接受返回的函数int*指针int*(并接受未定义数量的参数;请参阅注释).

一些例子(看起来不太好,它只是构造成包含所提到的声明):

#include <stdio.h>

static int a = 10;
int* f1() {
    return &a;
}

static int b;
int* f2(int *j, int*(*f)()) {
    b = *j + *f();
    // this is just for demonstrational purpose, such usage
    // of global variable makes this function not thread-safe
    return &b;
} 


int main(int argc, char *argv[]) {
    int * (*ptr1)();
    int * (*ptr2) (int * , int * (*)());
    ptr1 = f1;
    ptr2 = f2;

    int i = 42;
    int *pi = ptr2(&i, ptr1);
    printf("%d\n", *pi);

    return 0;
}

// prints 52

Answer 2

cdecl 是你的朋友:

$ cdecl explain 'int * (*x) (int * , int * (*)())'
declare x as pointer to function (pointer to int, pointer to function returning pointer to int) returning pointer to int