Question

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

I’d like to know what type is it ? , can someone give an example of a declaration using this type.

any help would be great.

thanks.

Answer 1

It is a pointer to function that returns int* and accepts int* and pointer to function that returns int* (and accepts undefined number of parameters; see comments).

Some example (does not look very nice, it is just constructed to contain the mentioned declaration):

#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