How can I pass an array to a function that cannot modify it?

Question

I'm programming in C and I want to pass an array to a function; this function cannot modify the elements of the array. What is the correct syntax for the arguments of the function?

void func(const Foo array_in[])

or

void func(Foo const array_in[])

or maybe they are the same? Thank you.

Answer 1

You should use pointer to constant in order to handle that:

#include<stdio.h>

void fun(const int *ptr)//pointer to constant - array boils down to pointer when passed to function
{
    ptr[0]=9;        //ERROR: Read-Only
}

int main(void)
{
    int arr[]={1,2,3,4};

    fun(arr);
    return 0;    
}

NOTE: Do not confuse it with constant pointer