is_resource

Example

Check if a variable is a resource:

 <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">echo</span> <span class="token string double-quoted-string">"File is open"</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
  <span class="token keyword">echo</span> <span class="token string double-quoted-string">"Error open file"</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token delimiter important">?></span></span>

Try it yourself