在C中返回字符串数组（char *）

Question

So imagine this fairly simple scenario. I have some function that does some manipulations and ends up returning an array of char pointers. For the sake of simplicity, let that function take no arguments:

#include <stdio.h>

char **func(void);

int main() {
    printf("%s\n", func()[0]);
    return 0;
}

char **func() {
    static char arr[3][10] = {"hi", "bye", "cry"};
    return arr;
}

I want to be able to access this array in my main() function. I make the array static in order to avoid returning the address to a local variable defined in the scope of func() . This code compiles, but with a warning:

warning: return from incompatible pointer type [-Wincompatible-pointer-types]

return arr;

^

But what should I make the return argument then? A pointer to a char array? I thought that in C returning an array is bad practice.

Running this program results in an unhelpful segmentation fault.

So what am I doing incorrectly? Can I not return a pointer to an array of char pointers? Hence, a char ** ? Am I conflating array/pointer decay? How would I return an array of strings? Is there a way to return a string array without the use of the static keyword?

Edit: Surely you all are able to empathize with my confusion? It's not like the array-pointer decay functionality of C is trivial to reason about.

Answer 1

In the statement return arr; , arr will decay to pointer to an array of 10 chars, ie of type char (*)[10] while return type of your function is char ** . Both pointer types are incompatible.
You can change the type of arr in the declaration from array of arrays to array of pointers.

static char *arr[3] = {"hi", "bye", "cry"};   

or you can change the return type of the function to char (*)[10]

char (*func())[10] {...}

Answer 2

The array:

static char arr[3][10] = {"hi", "bye", "cry"}; 

is an array of arrays of 10 characters. This is NOT compatible with char **.

Try

static char *arr[] = {"hi", "bye", "cry"};

instead.