eld</span> : <code class="type"><a href="Obj.html#TYPEt">t</a> -&gt; int -&gt; <a href="Obj.html#TYPEt">t</a> -&gt; unit</code></pre><div class="info ">
<div class="info-desc">
<p>When using flambda:</p>

<p><code class="code">set_field</code> MUST NOT be called on immutable blocks.  (Blocks allocated
    in C stubs, or with <code class="code">new_block</code> below, are always considered mutable.)</p>

<p>The same goes for <code class="code">set_double_field</code> and <code class="code">set_tag</code>.  H