Can I call memcpy() and memmove() with “number of bytes” set to zero?

Question

Do I need to treat cases when I actully have nothing to move/copy with memmove()/memcpy() as edge cases

int numberOfBytes = ...
if(         


        

Answer 1

As said by @You, the standard specifies that the memcpy and memmove should handle this case without problem; since they are usually implemented somehow like

void *memcpy(void *_dst, const void *_src, size_t len)
{
    unsigned char *dst = _dst;
    const unsigned char *src = _src;
    while(len-- > 0)
        *dst++ = *src++;
    return _dst;
}

you should not even have any performance penality other than the function call; if the compiler supports intrinsics/inlining for such functions, the additional check may even make the code a micro-little-bit slower, since the check is already done at the while.