Can I change an initialized char pointer via function?

Question

This is my main.c:

#include 

void changeStuff(char *stuff){
    stuff=  \"Hello everyone\";
}

int main(int argc, char **argv) {
            


        

Answer 1

In C, function arguments are passed-by-value. In order to modify a pointer value, you need to pass a pointer to the pointer, like:

#include <stdio.h>

void changeStuff(char **stuff){
    *stuff=  "Hello everyone";
}

int main(int argc, char **argv) {
    char *stuff;
    changeStuff(&stuff);
    printf("%s\n", stuff);
    return 0;
}

Note that it's not a good idea to directly pass user-defined values to printf(). See: How can a Format-String vulnerability be exploited?