为什么在特定情况下需要 memcpy

Question

In the following function:

void cp (char **x, char ** y) {
    while (*x) {
        * y = malloc(strlen (*x)+1);
        // * y++ = *x++;
        memcpy (*y++, *x++, strlen (*x) + 1);
    }
}

Why do I need to use memcpy ? Why can't I just use * y++ = * x++ . When I try doing it that way, I get a segfault when trying to free that memory.

Answer 1

x and y are char** s. If you just do * y++ = * x++ , then you're making the intermediate pointers point to the same place, rather than actually copying the data from the first location to the second.