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title: nng_pipe_id(3)
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<h1>nng_pipe_id(3)</h1>
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<h2 id="_name">NAME</h2>
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<p>nng_pipe_id - return numeric pipe identifier</p>
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<h2 id="_synopsis">SYNOPSIS</h2>
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<pre class="pygments highlight"><code data-lang="c"><span></span><span class="tok-cp">#include</span><span class="tok-w"> </span><span class="tok-cpf">&lt;nng/nng.h&gt;</span>

<span class="tok-kt">int</span><span class="tok-w"> </span><span class="tok-nf">nng_pipe_id</span><span class="tok-p">(</span><span class="tok-n">nng_pipe</span><span class="tok-w"> </span><span class="tok-n">p</span><span class="tok-p">);</span></code></pre>
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<h2 id="_description">DESCRIPTION</h2>
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<p>The <code>nng_pipe_id()</code> function returns a positive identifier for the pipe <em>p</em>,
if it is valid.
Otherwise it returns <code>-1</code>.</p>
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A pipe is considered valid if it was ever created by the socket.
Pipes that are allocated on the stack or statically should be
initialized with the macro
<a href="nng_pipe.5.html#NNG_PIPE_INITIALIZER"><code>NNG_PIPE_INITIALIZER</code></a> to ensure that
they cannot be confused with a valid pipe.
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<h2 id="_return_values">RETURN VALUES</h2>
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<p>This function returns the positive value for the pipe identifier, or
<code>-1</code> if the pipe is invalid.</p>
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<h2 id="_errors">ERRORS</h2>
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<p>None.</p>
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<h2 id="_see_also">SEE ALSO</h2>
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<p><a href="nng_pipe.5.html">nng_pipe(5)</a>,
<a href="nng.7.html">nng(7)</a></p>
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