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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><link rel="STYLESHEET" type="text/css" href="../../wrs.css"><title>WindNet STREAMS Components WindNet STREAMS for Tornado </title></head><body bgcolor="FFFFFF"><p class="navbar" align="right"><a href="index.html"><img border="0" alt="[Contents]" src="../../icons/contents.gif"></a><a href="streams.doc10.html"><img border="0" alt="[Prev]" src="../../icons/prev.gif"></a><a href="streams.doc12.html"><img border="0" alt="[Next]" src="../../icons/next.gif"></a></p><font face="Helvetica, sans-serif" class="sans"><h3 class="H2"><i><a name="81027" class="autotag">3.5 Unsupported Features</a></i></h3></font><dl class="margin"><dd><dl class="margin"><dd><div class="Item"><a name="81028" class="autotag"> </a>Signals</div><dl class="margin"><dd><div class="Indent"><a name="95327" class="autotag"> </a>UNIX signal semantics are not directly applicable to multi-threaded environments, like VxWorks, where families of processes are not supported. This functionality is not supported by WindNet STREAMS.</div><br><div class="Indent"><a name="91210" class="autotag"> </a>Do not send <b>M_SIG</b> or <b>M_PCSIG</b> messages from STREAMS drivers or modules to user applications because WindNet STREAMS stream heads will ignore them. The user applications that communicate with WindNet STREAMS drivers also cannot make use of signal handlers to trap signals originating from the drivers. Applications cannot make the <b class="routine"><i class="routine">ioctl</i></b><b>( )</b> call with the command <b>I_SETSIG</b>. The <b class="routine"><i class="routine">poll</i></b><b>( )</b> call under WindNet STREAMS does not generate <b class="keyword">sigpoll</b> signals, as it does in UNIX. </div><br></dd></dl><div class="Item"><a name="81010" class="autotag"> </a>Poll over non-STREAMS file descriptors</div><dl class="margin"><dd><div class="Indent"><a name="95329" class="autotag"> </a>WindNet STREAMS provides the <b class="routine"><i class="routine">poll</i></b><b>( )</b> routine to perform I/O multiplexing among many STREAMS file descriptors. However, <b class="routine"><i class="routine">poll</i></b><b>( )</b> cannot be used to perform I/O multiplexing over non-STREAMS file descriptors. Applications requiring poll functionality over non-STREAMS file descriptors should use the VxWorks <b class="routine"><i class="routine">select</i></b><b>( )</b> routine. </div><br></dd></dl><div class="Item"><a name="81012" class="autotag"> </a>Unsupported <i class="acronym_lc">ioctl</i> commands</div><dl class="margin"><dd><div class="Indent"><a name="95331" class="autotag"> </a>WindNet STREAMS does not support the <i class="acronym_lc">ioctl</i> commands <b>I_SENDFD</b> and <b>I_RECVFD</b>. These functions share and pass file descriptors in operating systems like UNIX, where file descriptors are maintained on a process basis. In an environment like VxWorks, the file descriptor table is maintained globally and all tasks have access to any file descriptor, obviating functions like <b>I_SENDFD</b> and <b>I_RECVFD</b>. </div><br></dd></dl><div class="Item"><a name="81014" class="autotag"> </a>Unsupported STREAMS set processor level (spl) routines</div><dl class="margin"><dd><div class="Indent"><a name="95333" class="autotag"> </a>WindNet STREAMS does not support the STREAMS-specific spl routines <b class="routine"><i class="routine">splstr</i></b><b>( )</b> and <b class="routine"><i class="routine">splx</i></b><b>( )</b>. Developers of STREAMS drivers under WindNet STREAMS are expected to use WindNet STREAMS synchronization primitives, as well as VxWorks semaphores, to protect critical regions of code in their drivers and modules. </div><br></dd></dl></dd></dl></dd></dl><a name="foot"><hr></a><p class="navbar" align="right"><a href="index.html"><img border="0" alt="[Contents]" src="../../icons/contents.gif"></a><a href="streams.doc10.html"><img border="0" alt="[Prev]" src="../../icons/prev.gif"></a><a href="streams.doc12.html"><img border="0" alt="[Next]" src="../../icons/next.gif"></a></p></body></html><!---This file generated April 10, 1998, 12:25PM PDTby WRS Documentation (jeff), Wind River Systems, Inc. conversion tool: Quadralay WebWorks Publisher 3.5.0 template: CSS Template, Jan 1998 - Jefro --->⌨️ 快捷键说明
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