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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> I/O System </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="GuideIX.html"><img border="0" alt="[Index]" src="icons/index.gif"></a><a href="c-iosys.html"><img border="0" alt="[Top]" src="icons/top.gif"></a><a href="c-iosys7.html"><img border="0" alt="[Prev]" src="icons/prev.gif"></a><a href="c-iosys9.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="85062">3.8 Differences Between VxWorks and Host System I/O</a></i></h3></font><dl class="margin"><dl class="margin"><dd><p class="Body"><a name="85063"> </a>Most commonplace uses of I/O in VxWorks are completely source-compatible with I/O in UNIX and Windows. However, note the following differences:</p><b class="BulletHead-run"><li type="disc"><a name="85064"> </a><font face="Helvetica, sans-serif" size="-1" class="sans">Device Configuration. . </font></b><dl class="margin"><dd><div class="Indent"><a name="86950"> </a>In VxWorks, device drivers can be installed and removed dynamically.</div><br></dl><b class="BulletHead-run"><li type="disc"><a name="85065"> </a><font face="Helvetica, sans-serif" size="-1" class="sans">File Descriptors. . </font></b><dl class="margin"><dd><div class="Indent"><a name="86951"> </a>In UNIX and Windows, <i class="acronym_lc">fd</i>s are unique to each process. In VxWorks, <i class="acronym_lc">fd</i>s are global entities, accessible by any task, except for standard input, standard output, and standard error (0, 1, and 2), which can be task specific.</div><br></dl><b class="BulletHead-run"><li type="disc"><a name="85066"> </a><font face="Helvetica, sans-serif" size="-1" class="sans">I/O Control. . </font></b><dl class="margin"><dd><div class="Indent"><a name="86952"> </a>The specific parameters passed to <b class="routine"><i class="routine">ioctl</i></b><b>(</b> <b>)</b> functions can differ between UNIX and VxWorks.</div><br></dl><b class="BulletHead-run"><li type="disc"><a name="86957"> </a><font face="Helvetica, sans-serif" size="-1" class="sans">Driver Routines. . </font></b><dl class="margin"><dd><div class="Indent"><a name="86958"> </a>In UNIX, device drivers execute in system mode and are not preemptible. In VxWorks, driver routines are in fact preemptible because they execute within the context of the task that invoked them.</div><br></dl></dl></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="GuideIX.html"><img border="0" alt="[Index]" src="icons/index.gif"></a><a href="c-iosys.html"><img border="0" alt="[Top]" src="icons/top.gif"></a><a href="c-iosys7.html"><img border="0" alt="[Prev]" src="icons/prev.gif"></a><a href="c-iosys9.html"><img border="0" alt="[Next]" src="icons/next.gif"></a></p></body></html><!---by WRS Documentation (), Wind River Systems, Inc. conversion tool: Quadralay WebWorks Publisher 4.0.11 template: CSS Template, Jan 1998 - Jefro --->⌨️ 快捷键说明
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