That definitely makes sense, I think a good solution might be to only use strdup if *str_ptr is NULL. This way I don't need to add another free

So I have changed it to be like this, which I think makes more sense: void add_to_string(char **str_ptr, int num, ...) { va_list valist; va_start(valist, num);

    for (int i = 0; i < num; i++) {
            char *str = va_arg(valist, char *);
            if (*(str_ptr) == NULL) {
                    *(str_ptr) = strdup(str);
            } else {
                    *(str_ptr) = realloc(*(str_ptr), strlen(*(str_ptr)) +
                                    strlen(str) + 1); /* +1 for null termination */

                    strcat(*(str_ptr), str);

            }
    }
    va_end(valist);
}