char **s versus char *s[], when and how to use each one?

Question

If I use char *s[], I can do the following:

char *s[] = {"foo", "bar", "foobar", "whatever", "john", "doe"};

What is the difference with **s? How do I use the char **s instead of char *s[] in that case?

Example: int main (int argc, char **argv) instead of *argv[]

Answer 1

For function parameters, there is no difference.

Otherwise:

char *s[];

s is an array of pointer to char. And

char **s;

s is a pointer to pointer to char.

You use the former if you need an array of pointer to char, and you use the latter if you need a pointer to a pointer to a char.

Answer 2

As function parameters, there is no difference whatsoever. They are equivalent.

void f(int** p);
void f(int* p[]);
void f(int* p[42]);

These three declarations are equivalent.

As objects, they have different types;

char *s[] = {"foo", "bar", "foobar", "whatever", "john, "doe"};

s is an array of 6 pointers to char sizeof(s) == 6*sizeof(void*)

char **s;

s is a pointer to pointer to char. sizeof(s) == sizeof(void*)