400 lines
12 KiB
HTML
400 lines
12 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>QsoStartRecv()--Start Asynchronous Receive Operation</title>
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<!-- Begin Header Records -->
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<!-- Created by Steve Simonson for V5R1 -->
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<!-- Edited by Kersten Feb 02 -->
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<!-- End Header Records -->
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<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</head>
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<body>
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<a name="Top_Of_Page"></a>
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<!--Java sync-link-->
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<script type="text/javascript" language="Javascript" src="../rzahg/synch.js">
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</script>
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<h2>QsoStartRecv()--Start Asynchronous Receive Operation</h2>
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<div class="box" style="width: 60%;">
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<br>
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Syntax
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<pre>
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#include <qsoasync.h>
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int QsoStartRecv (int socketDescriptor,int IOCompletionPort,
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Qso_OverlappedIO_t * communicationsArea)
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</pre>
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<br>
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Service Program Name: QSOSRV3<br>
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<!-- iddvc RMBR -->
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<p>The QsoStartRecv function is used to initiate a asynchronous receive
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operation. The supplied buffer cannot be reused by the calling application
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until the receive is complete or the I/O completion port specified on the
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QsoStartRecv has been destroyed. This API only supports sockets with an address
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family of AF_INET or
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AF_INET6 and type
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SOCK_STREAM.</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt><strong>int socketDescriptor</strong> (Input)</dt>
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<dd>The socket descriptor that should be used to receive data into the
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specified buffer.<br>
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<br>
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</dd>
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<dt><strong>int IOCompletionPort</strong> (Input)</dt>
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<dd>The I/O completion port that should be posted when the operation
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completes.<br>
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<br>
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</dd>
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<dt><strong>Qso_OverlappedIO_t</strong> * communicationsArea
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(Input/Output)</dt>
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<dd>A pointer to a structure that contains the following information:<br>
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<br>
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<table cellpadding="5">
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<!-- cols="20 80" -->
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<tr>
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<td align="left" valign="top"><em>descriptorHandle</em></td>
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<td align="left" valign="top">(Input) - The descriptor handle is application
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specific and is never used by the system. This field is intended to make it
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easier for the application to keep track of information regarding a given
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socket connection.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>buffer</em></td>
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<td align="left" valign="top">(Input) - A pointer to a buffer into which data
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should be read.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>bufferLength</em></td>
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<td align="left" valign="top">(Input) - The length of the buffer into which
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data should be read. Also represents the amount of data requested.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>postFlag</em></td>
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<td align="left" valign="top">(Input) - The postFlag indicates if this
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operation should be posted to the I/O completion port even if it completes
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immediately.
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<ul>
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<li>A 0 value indicates that if the operation is already complete upon return
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to the application, then do not post to the I/O completion port.</li>
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<li>A 1 value indicates that even if the operation completes immediately upon
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return to the application, the result should still be posted to the I/O
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completion port.</li>
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</ul>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>postFlagResult</em></td>
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<td align="left" valign="top">(Output) - This field is valid if QsoStartRecv()
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returns with 1 and postFlag was set to 1. In this scenario, postFlagResult set
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to 1 denotes the operation completed and been posted to the I/O completion port
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specified. A value of 0 denotes the operation could not be completed
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immediately, but will be handled asynchronously.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>fillBuffer</em></td>
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<td align="left" valign="top">(Input) - The fillBuffer flag indicates when this
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operation should complete. If the fillBuffer flag is 0, then the operation will
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complete as soon as any data is available to be received. If the fillBuffer
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flag is non-zero, this operation will not complete until enough data has been
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received to fill the buffer, an end-of-file condition occurs on the socket, or
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an error occurs on a socket.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>returnValue</em></td>
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<td align="left" valign="top">(Output) - When QsoStartRecv() completes
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synchronously (function return value equals 0), then this field indicates the
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number of bytes that were actually received. When the recv operation completes
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asynchronously, this field contains indication of success or failure. Zero
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returned denotes end-of-file state.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>errnoValue</em></td>
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<td align="left" valign="top">(Output) - When the operation completes
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asynchronously and returnValue is negative, this field contains an errno to
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indicate the error with which the operation eventually failed.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>operationCompleted</em></td>
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<td align="left" valign="top">(Output) - If the operation is posted to the I/O
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completion port, this field is updated to indicate that the operation was a
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QsoStartRecv().</td>
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</tr>
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<tr>
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<td align="left" valign="top">
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<em>secureDataTransferSize</em></td>
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<td align="left" valign="top">Not used.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>bytesAvailable</em></td>
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<td align="left" valign="top">Not used.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>operationWaitTime</em></td>
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<td align="left" valign="top">(Input) - A timeval structure which specifies the
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maximum time allowed for this operation to complete asynchronously.
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<pre>
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struct timeval {
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long tv_sec; /* second */
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long tv_usec; /* microseconds */
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};
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</pre>
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<p>If this timer expires, the operation will be posted to the I/O completion
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port with <em>errnoValue</em> set to EAGAIN.</p>
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<p>If this field is set to zero, the operation's asynchronous completion will
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not be timed.</p>
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<p>If socketDescriptor is closed before the operation completes or times out,
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the operation will be posted to the I/O completion port with
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<em>errnoValue</em> set to ECLOSED.</p>
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<p>The minimum operationWaitTime is 1 second. The microseconds field (tv_usec)
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in the timeval is not used and must be set to zero.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>postedDescriptor</em></td>
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<td align="left" valign="top">Not used - Must be set to zero.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>reserved1</em></td>
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<td align="left" valign="top">(Input) - Must be set to hex zeroes.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>reserved2</em></td>
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<td align="left" valign="top">(Input) - Must be set to hex zeroes.</td>
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</tr>
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</table>
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</dd>
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</dl>
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<br>
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<h3>Authorities</h3>
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<p>No authorization is required.</p>
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<br>
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<h3>Return Values</h3>
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<p>QsoStartRecv() returns an integer. Possible values are:</p>
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<ul>
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<li>-1 - The function was not started because an error occurred. Inspect the
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<strong>errno</strong> to determine the cause of the failure.</li>
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<li>0 - The function has already completed. The Qso_OverlappedIO_t
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communications structure has been updated but nothing has or will be posted to
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the I/O completion port for this operation. Inspect the returnValue in the
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Qso_OverlappedIO_t communications structure to determine the number of bytes
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received.</li>
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<li>1 - The function has been started. When the function completes (or times out if operationWaitTime was
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specified), the
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Qso_OverlappedIO_t communications structure will be updated with the results
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and the I/O completion port will be posted.</li>
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</ul>
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<br>
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<h3>Errno Conditions</h3>
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<p>When QsoStartRecv() fails, errno can be set to one of the following:</p>
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<table cellpadding="5">
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<!-- cols="15 85" -->
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<tr>
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<td align="left" valign="top"><em>[EINVAL]</em></td>
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<td align="left" valign="top">A buffer length or I/O completion port or
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reserved field specified was not valid or postedDescriptor was not zero or operationWaitTime.tv_sec
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was negative or operationWaitTime.tv_usec was not zero.<br>
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<br>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[ETRUNC]</em></td>
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<td align="left" valign="top">Data was truncated on an input, output, or update
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operation. Data has been lost.</td>
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</tr>
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</table>
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<p><strong>Note:</strong> The rest of the errno values from <a href=
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"recv.htm">recv()</a> also apply to QsoStartRecv().</p>
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<br>
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<h3>Error Messages</h3>
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<table width="100%" cellpadding="5">
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<!-- cols="15 85" -->
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<tr>
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<th align="left" valign="top">Message ID</th>
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<th align="left" valign="top">Error Message Text</th>
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</tr>
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<tr>
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<td width="15%" valign="top">CPFA081 E</td>
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<td width="85%" valign="top">Unable to set return value or error code.</td>
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</tr>
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<tr>
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<td align="left" valign="top">CPE3418 E</td>
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<td align="left" valign="top">Possible APAR condition or hardware failure.</td>
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</tr>
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<tr>
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<td align="left" valign="top">CPF9872 E</td>
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<td align="left" valign="top">Program or service program &1 in library
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&2 ended. Reason code &3.</td>
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</tr>
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</table>
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<br>
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<br>
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<h3>Usage Notes</h3>
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<ol>
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<li>If QsoStartRecv() partially fills a buffer and then encounters an EFAULT
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condition, the QsoStartRecv() will complete with the ETRUNC error value to
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indicate that some data has been lost.<br>
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<br>
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</li>
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<li>A buffer that is given to QsoStartRecv() must not be used by the
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application again until either it is returned by QsoWaitForIOCompletion() or is
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reclaimed by issuing a close() on the socket descriptor or issuing a
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QsoDestroyIOCompletionPort() on the I/O completion port. If a buffer is given
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to QsoStartRecv() to be filled, and it is later detected during QsoStartRecv
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processing that the buffer has been freed, it may produce an unrecoverable
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condition on the socket for which the QsoStartRecv() was issued. If this
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occurs, an ECONNABORTED error value will be returned.<br>
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<br>
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</li>
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<li>It is not recommended to intermix QsoStartRecv() and blocking I/O (that is,
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recv()) on the same socket. If this condition occurs, then pending asynchronous
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send I/O will be serviced first before the blocking I/O.<br>
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<br>
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</li>
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<li>Socket option SO_RCVLOWAT is not supported by this API. Semantics similar
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to SO_RCVLOWAT can be obtained using the fillBuffer field in the
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Qso_OverLappedIO_t structure.<br>
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<br>
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</li>
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<li> Socket option SO_RCVTIMEO
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is not supported by this API. Semantics similar to SO_RCVTIMEO can be obtained
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using the operationWaitTime field in the Qso_OverLappedIO_t structure.</li>
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</ol>
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<br>
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<h3>Related Information</h3>
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<ul>
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<li><a href="createiocompletionport.htm">QsoCreateIOCompletionPort()</a>--Create
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I/O Completion Port<br>
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<br>
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</li>
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<li><a href="destroyiocompletionport.htm">QsoDestroyIOCompletionPort()</a>--Create
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I/O Completion Port<br>
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<br>
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</li>
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<li><a href="postiocompletion.htm">QsoPostIOCompletionPort()</a>--Post Request on
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I/O Completion Port<br>
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<br>
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</li>
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<li><a href="startsend.htm">QsoStartSend</a>--Start Asynchronous Send
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Operation<br>
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<br>
|
||
|
|
</li>
|
||
|
|
|
||
|
|
<li><a href="waitforiocompletion.htm">QsoWaitForIOCompletion()</a>--Wait for I/O
|
||
|
|
Completion Operation<br>
|
||
|
|
<br>
|
||
|
|
</li>
|
||
|
|
|
||
|
|
<li><a href="recv.htm">recv()</a>--Receive Data</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<br>
|
||
|
|
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
API introduced: V5R1
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<center>
|
||
|
|
<table cellpadding="2" cellspacing="2">
|
||
|
|
<tr align="center">
|
||
|
|
<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> |
|
||
|
|
<a href="unix.htm">UNIX-Type APIs</a> |
|
||
|
|
<a href="aplist.htm">APIs by category</a> </td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
</center>
|
||
|
|
</body>
|
||
|
|
</html>
|
||
|
|
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