📄 t_listen.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>t_listen</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4>NAME</h4><blockquote>t_listen - listen for a connection indication</blockquote><h4>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="xti.h.html">xti.h</a>>int t_listen( int fd, struct t_call *call)</code></pre></blockquote><h4>DESCRIPTION</h4><blockquote><pre><P><table bordercolor=#000000 border=1 align=center><tr valign=top><th align=center><b>Parameters</b><th align=center><b>Before call</b><th align=center><b>After call</b><tr valign=top><td align=left>fd<td align=center>x<td align=center>/<tr valign=top><td align=left>call-><td align=center>addr.maxlen<td align=center>x<tr valign=top><td align=left>call-><td align=center>addr.len<td align=center>/<tr valign=top><td align=left>call-><td align=center>addr.buf<td align=center>?<tr valign=top><td align=left>call-><td align=center>opt.maxlen<td align=center>x<tr valign=top><td align=left>call-><td align=center>opt.len<td align=center>/<tr valign=top><td align=left>call-><td align=center>opt.buf<td align=center>?<tr valign=top><td align=left>call-><td align=center>udata.maxlen<td align=center>x<tr valign=top><td align=left>call-><td align=center>udata.len<td align=center>/<tr valign=top><td align=left>call-><td align=center>udata.buf<td align=center>?<tr valign=top><td align=left>call-><td align=center>sequence<td align=center>/</table></pre><p>This function listens for aconnection indication from a calling transport user.The argument<I>fd</I>identifies the local transport endpoint where connectionindications arrive,and on return,<I>call</I>contains information describing the connection indication.The parameter<I>call</I>points to a<B>t_call</B>structure which contains the following members:<pre><code>struct netbuf addr;struct netbuf opt;struct netbuf udata;int sequence;</code></pre><p>In<I>call</I>,<I>addr</I>returns the protocol address of the calling transport user.This address is in a format usable in future calls to<i><a href="t_connect.html">t_connect()</a></i>.Note, however that<i><a href="t_connect.html">t_connect()</a></i>may fail for other reasons, for example [TADDRBUSY].<I>opt</I>returns optionsassociated with the connection indication,<I>udata</I>returns any user data sent by the caller on the connection request, and<I>sequence</I>is a number that uniquely identifies the returned connectionindication.The value of<I>sequence</I>enables the user to listen for multiple connection indicationsbefore responding to any of them.<p>Since this function returns values for the<I>addr</I>,<I>opt</I>and<I>udata</I>fields of<I>call</I>,the<I>maxlen</I>field of each must be set before issuing the<i>t_listen()</i>to indicate the maximum size of the buffer for each.If the <I>maxlen</I>field of <I>call->addr</I>,<I>call->opt</I>or <I>call->udata</I>is set to zero, no information is returned for this parameter.<p>By default,<i>t_listen()</i>executes in synchronous mode andwaits for a connection indication to arrive before returning to the user.However, if O_NONBLOCKis set via<i><a href="t_open.html">t_open()</a></i>or<i><a href="fcntl.html">fcntl()</a></i>,<i>t_listen()</i>executes asynchronously, reducingto a poll for existing connection indications.If none are available, it returns -1 and sets<I>t_errno</I>to [TNODATA].</blockquote><h4>VALID STATES</h4><blockquote>T_IDLE, T_INCON</blockquote><h4>ERRORS</h4><blockquote>On failure,<I>t_errno</I>is set to one of the following:<dl compact><dt>[TBADF]<dd>The specified file descriptor does not refer to a transport endpoint.<dt>[TBADQLEN]<dd>The argument<I>qlen</I>of the endpoint referenced by<I>fd</I>is zero.<dt>[TBUFOVFLW]<dd>The number of bytes allocated for an incoming argument<I>(maxlen)</I>is greater than 0 but notsufficient to store the value of that argument.The provider's state, as seen by the user, changes toT_INCON, andthe connection indication information to be returned in<I>call</I>is discarded.The value of<I>sequence</I>returned can be used to do a<i><a href="t_snddis.html">t_snddis()</a></i>.<dt>[TLOOK]<dd>An asynchronous event has occurred on this transport endpoint and requiresimmediate attention.<dt>[TNODATA]<dd>O_NONBLOCKwas set, but no connection indications had been queued.<dt>[TNOTSUPPORT]<dd>This function is not supported by the underlying transportprovider.<dt>[TOUTSTATE]<dd>The communications endpoint referenced by <I>fd</I>is not in one of the states in which a call to this function is valid.<dt>[TPROTO]<dd>This error indicates that a communication problem has been detected betweenXTI and the transport provider for which there is no other suitable XTIerror<I>(t_errno)</I>.<dt>[TQFULL]<dd>The maximum number of outstanding connection indications has beenreached for the endpoint referenced by<I>fd</I>.Note that a subsequent call to<i>t_listen()</i>may block until another incoming connection indicationis available. This can only occur if at least oneof the outstanding connection indications becomesno longer outstanding, for example through a call to<i><a href="t_accept.html">t_accept()</a></i>.<dt>[TSYSERR]<dd>A system error has occurred during execution of this function.</dl></blockquote><h4>CAVEATS</h4><blockquote>Some transport providers do not differentiate betweena connection indication and the connection itself.If this is the case, a successful return of<i>t_listen()</i>indicates an existing connection (see<xref href=ipsi></xref>).</blockquote><h4>RETURN VALUE</h4><blockquote>Upon successful completion, a value of 0 is returned. Otherwise,a value of -1 is returned and<I>t_errno</I>is set to indicate an error.</blockquote><h4>SEE ALSO</h4><blockquote><i><a href="fcntl.html">fcntl()</a></i>,<i><a href="t_accept.html">t_accept()</a></i>,<i><a href="t_alloc.html">t_alloc()</a></i>,<i><a href="t_bind.html">t_bind()</a></i>,<i><a href="t_connect.html">t_connect()</a></i>,<i><a href="t_open.html">t_open()</a></i>,<i><a href="t_optmgmt.html">t_optmgmt()</a></i>,<i><a href="t_rcvconnect.html">t_rcvconnect()</a></i>.</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -