Is there a better way to fetch this value from "char **"?

Question

I'm studying C in order to start doing some fun low-level code stuff, and I've stumbled into a scenario which I can't wrap my head around, and I'm sure it's because I don't have a lot of experience with it.

Currently my code is very simple: it takes some arguments, and gets the first parameter passed to main, and stores it as a path string. The first question that came to mind, was whether it would be correct to store the main params as char *args[] or char **args, and I decided to go with char **args since according to this question there could be some scenarios where the first would not be accessible, and I just wanted to make a code that would be as complete as possible, and learn the whys on the process.

Here's is the code:

int main(int argc, char **args) { if (args[1] == NULL) return 1; // Get path of input file char *path = &*args[1]; fputs(path, stdout); return 0; }

Given the code above, what would be a better way of fetching the value stored in *args[1]? It seems very cryptic when I look at it, and it took me a while to get to it as well.

My understanding is that char **args, is a pointer, to an array of pointers. Thus, if I'm to store a string or any other value for later use in one of the indexes of args, I would have to assign a new pointer to a memory location (*path), and assign the value of the given index to it (&*args[i]). Am I over complicating things? Or is this thought process correct?

Unless argc > 1 this is undefined behaviour. Check before accessing. — tadman
– tadman, Commented Apr 9, 2021 at 21:53

Vlad from Moscow · Accepted Answer · 2021-04-09 22:00:14Z

For starters these two function declarations

int main(int argc, char **args)

and

int main(int argc, char *args[])

are fully equivalent because the compiler adjusts the parameter that has an array type to pointer to the array element type.

In the initializer expression of this declaration

char *path = &*args[1];

applying the two operators & and * sequentially is redundant. So you may just write

char *path = args[1];

Also in general instead of the condition in the if statement

if ( args[1] == NULL) return 1;

it will be more safer to write

if ( argc < 2 ) return 1;

Barmar · Accepted Answer · 2021-04-09 21:52:48Z

You can simply write:

char *path = args[1];

& and * operators are inverses of each other, so &* or *& can simply be removed from an expression.

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