is_resource

例

変数がリソースであるかどうかを確認します。

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token variable">$ file</span> <span class="token operator">=</span> <span class="token function">fopen</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"test.txt"</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"r"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>

<span class="token keyword">if</span> <span class="token punctuation">（</span> <span class="token function">is_resource</span> <span class="token punctuation">（</span> <span class="token variable">$ file</span> <span class="token punctuation">）</span> <span class="token punctuation">）</span> <span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「ファイルが開いている」</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span><span class="token keyword">それ以外</span><span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「エラーファイル」</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token delimiter important">？></span></span>

自分で試してみてください