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<a name="getenv_002d_002d_002dlook-up-environment-variable"></a>
<h3 class="section">2.18 <code>getenv</code>&mdash;look up environment variable</h3>
<a name="index-getenv"></a>
<a name="index-environ"></a>
<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;stdlib.h&gt;
char *getenv(const char *<var>name</var>);

</pre></div>
<p><strong>Description</strong><br>
<code>getenv</code> searches the list of environment variable names and values
(using the global pointer &ldquo;<code>char **environ</code>&rdquo;) for a variable whose
name matches the string at <var>name</var>.  If a variable name matches,
<code>getenv</code> returns a pointer to the associated value.
</p>
<br>
<p><strong>Returns</strong><br>
A pointer to the (string) value of the environment variable, or
<code>NULL</code> if there is no such environment variable.
</p>
<br>
<p><strong>Portability</strong><br>
<code>getenv</code> is ANSI, but the rules for properly forming names of environment
variables vary from one system to another.
</p>
<p><code>getenv</code> requires a global pointer <code>environ</code>.
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