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7<title>GetHeaderField</title>
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10<h1><CODE>nn::http::Connection::GetHeaderField</CODE> Member Function</h1>
11<h2>Syntax</h2>
12    <div class="section">
13      <pre class="definition">
14<a href="../../../nn/Result/Overview.html">nn::Result</a> GetHeaderField(
15     const char * pLabel,
16     char * pFieldBuf,
17     size_t bufSize,
18     size_t * pFieldLengthCourier = NULL
19) const;
20<a href="../../../nn/Result/Overview.html">nn::Result</a> GetHeaderField(
21     const char * pLabel,
22     char * pFieldBuf,
23     size_t bufSize,
24     const <a href="../../../nn/fnd/TimeSpan/Overview.html">nn::fnd::TimeSpan</a> & timeout,
25     size_t * pFieldLengthCourier = NULL
26) const;
27</pre>
28    </div>
29<h2>List of Overloaded Member Functions</h2>
30    <div class="section">
31      <table class="members">
32        <tr>
33          <td>
34<a href="./GetHeaderField(0).html"><CODE>GetHeaderField(const char *, char *, size_t, size_t *)</CODE> </a>
35          </td>
36<td>Gets the field value that matches the specified label. This field value is obtained from the message header of the HTTP response that was received.</td>
37        </tr>
38        <tr>
39          <td>
40<a href="./GetHeaderField(1).html"><CODE>GetHeaderField(const char *, char *, size_t, const nn::fnd::TimeSpan &, size_t *)</CODE> </a>
41          </td>
42<td>This version of <a href="../../../nn/http/Connection/GetHeaderField.html"><CODE>GetHeaderField</CODE></a> has a timeout.</td>
43        </tr> </table>
44    </div>
45<h2>Description of <CODE>GetHeaderField(const char *, char *, size_t, size_t *)</CODE></h2>
46<div class="section"><p>This function blocks until the header is completely received. The receive operation completes if the following conditions are met.<br />・ All header data has been received.<br />・ The operation was cancelled.<br />・ A communication error occurred (for example, DNS name resolution failed).<br />If the header was already completely received by another function, this function will return the response immediately.<br /><br /><BR><B>Note:</B> If the <SPAN class="argument">pFieldBuf</SPAN> size is smaller than the field value size, as much data is stored in <SPAN class="argument">pFieldBuf</SPAN> as will fit, and the field value size is stored in <SPAN class="argument">pFieldLengthCourier</SPAN>.<br /><BR><B>Note:</B> If <SPAN class="argument">pFieldBuf</SPAN><CODE>==NULL</CODE> or <SPAN class="argument">bufSize</SPAN><CODE>==0</CODE>, and if <SPAN class="argument">pFieldLengthCourier</SPAN><CODE>!=NULL</CODE>, the field length is stored in <SPAN class="argument">pFieldLengthCourier</SPAN>.<br /><BR><B>Note:</B> Unlike the version of <CODE><a href="../../../nn/http/Connection/GetHeaderField.html">GetHeaderField</a></CODE> that includes a timeout, this function does not time out. In other words, control will not return from this function until processing has ended. In environments where communications are slow you can expect a long time to pass before processing ends and control returns from this function.<br /></p><!-- write here --></div>
47<h2>Description of <CODE>GetHeaderField(const char *, char *, size_t, const nn::fnd::TimeSpan &, size_t *)</CODE></h2>
48<div class="section"><p>Other than allowing the user to specify a timeout, this version functions identically to <a href="../../../nn/http/Connection/GetHeaderField.html"><CODE>GetHeaderField</CODE></a>. For feature details, see the function reference for the version without a timeout. Returns <a href="../../../nn/http/ResultTimeout/Overview.html"><CODE>ResultTimeout</CODE></a> if no HTTP response header has been fully received within the timeout period. If <CODE>ResultTimeout</CODE> is returned, the connection is automatically canceled. (In other words, the function internally implements <a href="../../../nn/http/Connection/Cancel.html"><CODE>Cancel</CODE></a>.)<br /></p><!-- write here --></div>
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