How to parse command-line arguments from a separate function - c

Question

I am attemping to parse a command-line argument from one function process_command_line which I will then use in a main function. The second command-line argument enables the name of a file input to be submitted, which will later be used to read/write files. For the time being, I will just print out the argument within the main function to ensure that it is functioning correctly. I have had no issues parsing integers using this separate function method, but cannot get a correct output when trying to parse an input file name.
EDIT: I think my issue lies in the second function where I have a line saying argv[1] = input_file;
My attempt:
#include <stdio.h>
#include <stdlib.h>
int process_command_line(int argc, char *argv[]); //declaration for command-line function
char str2[100];
int main(int argc, char *argv[]) {
printf("%s", str2);
getchar();
return 0;
}
//This function reads in the arguments
int process_command_line(int argc, char *argv[]) {
if (argc < 2) {
fprintf(stderr, "Error: Missing program arguments.\n");
exit(1);
}
//first argument is always the executable name (argv[0])
//second argument reads in the input file name
strcpy(str2, argv[1]); //I think this is where the problem lies
}

Answer 1

With the help of users on this question, here is my updated and functioning solution. The problem was that I wasn't calling the second function within my main function.
My solution:
#include <stdio.h>
#include <stdlib.h>
int process_command_line(int argc, char *argv[]); //declaration for command-line function
char str2[100];
int main(int argc, char *argv[]) {
process_command_line(argc, argv); //This was missing in my first attempt
printf("%s", str2);
getchar();
return 0;
}
//This function reads in the arguments
int process_command_line(int argc, char *argv[]) {
if (argc < 2) {
fprintf(stderr, "Error: Missing program arguments.\n");
exit(1);
}
//first argument is always the executable name (argv[0])
//second argument reads in the input file name
strcpy(str2, argv[1]);
}