Pointer cast

Question

void    *ft_memchr(const void *s, int c, size_t n)
{
    while (n > 0)
    {
        if (*(unsigned char *) s == c)
        {
            return ((void *)s);
        }
        s++;
        n--;
    }
    return (NULL);
}

What would this be *(unsigned char *)s?

I understand it’s a cast because it’s a void and such, but what I can’t understand and can’t find material to understand is these pointers, for example the first * I no longer know what it is, but from what I’ve seen its existence it already leaves me totally in doubt of the existence of the second pointer.

Answer 1

The (unsigned char *) is a cast from any address to an unsigned char type address*.

A unsigned char has a byte size.

The first * is to de-reference the address of s.

As the address of s is now interpreted as a unsigned char will be de-referenced one byte from the address.

And this byte is compared with the variable c.