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

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

int numberOfBytes = ...
if( numberOfBytes != 0 ) {
    memmove( dest, source, numberOfBytes );
}

or should I just call the function without checking

int numberOfBytes = ...
memmove( dest, source, numberOfBytes );

Is the check in the former snippet necessary?