why for structure with flexible array member, we shouldn't use structure assignment for copying : <p>I'm currently learning c structure, especially structure with flexible array member. </p>

<p>Given a structure flexible array </p>

<pre><code>struct flex
{
    size_t count;
    double average;
    double scores[]; // flexible array member
};
</code></pre>

<p>I have been told not to use assignment for copying </p>

<p><a href="https://i.stack.imgur.com/bfxVo.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bfxVo.png" alt="enter image description here"></a></p>

<p>I'm not sure why this operation only copy the non-flexible member of  the structure. </p>

<p>Could someone please explain to me the underlying reasons why this is the case? </p>
