Question

I happen to have several functions which access different arguments of the program through the argv[] array. Right now, those functions are nested inside the main() function because of a language extension the compiler provides to allow such structures.

I would like to get rid of the nested functions so that interoperability is possible without depending on a language extension.

First of all I thought of an array pointer which I would point to argv[] once the program starts, this variable would be outside of the main() function and declared before the functions so that it could be used by them.

So I declared such a pointer as follows:

char *(*name)[];

Which should be a pointer to an array of pointers to characters. However, when I try to point it to argv[] I get a warning on an assignment from an incompatible pointer type:

name = &argv;

What could be the problem? Do you think of another way to access the argv[] array from outside the main() function?

Answer 1

char ** name;
...
name = argv;

will do the trick 🙂

you see char *(*name) [] is a pointer to array of pointers to char. Whereas your function argument argv has type pointer to pointer to char, and therefore &argv has type pointer to pointer to pointer to char. Why? Because when you declare a function to take an array it is the same for the compiler as a function taking a pointer. That is,

void f(char* a[]);
void f(char** a);
void f(char* a[4]);

are absolutely identical equivalent declarations. Not that an array is a pointer, but as a function argument it is

HTH