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style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>操作系统的计算机。</span></span><a
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<h3><span style='mso-bookmark:_Toc16587483'><a name="_Toc45704123"></a><a
name="_实验内容与步骤"></a><span style='mso-bookmark:_Toc45704123'>实验内容与步骤</span></span></h3>
<p class=MsoNormal style='text-indent:21.0pt'><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>并发程序的设计关键是使用创建进程的系统调用，使一个程序运行时可以生成几个同时运行的程序，如果程序中没有创建进程的动作则为顺序程序设计。</span></span></p>
<p class=MsoNormal style='text-indent:21.0pt'><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>本实验中的并发程序例子完成两个程序</span><span lang=EN-US>child</span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>和</span><span
lang=EN-US>father</span></span><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>之间的数据传递工作，具体做法分为四步。</span></span></p>
<p class=MsoNormal style='text-indent:21.0pt'><span style='mso-bookmark:_Toc16587483'><b
style='mso-bidi-font-weight:normal'><span style='font-family:楷体_GB2312;
mso-ascii-font-family:"Times New Roman"'>步骤</span></b></span><span
style='mso-bookmark:_Toc16587483'><b style='mso-bidi-font-weight:normal'><span
lang=EN-US style='mso-fareast-font-family:楷体_GB2312'>1</span></b></span><span
style='mso-bookmark:_Toc16587483'><b style='mso-bidi-font-weight:normal'><span
style='font-family:楷体_GB2312;mso-ascii-font-family:"Times New Roman"'>：</span></b></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>编制并发程序</span><span
lang=EN-US>pipeline.c</span></span><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。</span></span></p>
<p class=MsoNormal style='text-indent:21.0pt'><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>单击红帽子，在“</span><span lang=EN-US>GNOME</span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>帮助”菜单中单击“附件”</span><span
lang=EN-US>-</span></span><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>“文本编辑器”命令，在文本编辑中键入程序并保存为</span><span lang=EN-US>pipeline.c</span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>。</span></span></p>
<p class=MsoNormal style='text-indent:21.0pt'><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>在该程序中定义管道和文件描述符，并且创建子进程</span><span lang=EN-US>child</span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>。该程序用到的系统调用有</span><span
lang=EN-US>pipe() </span></span><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>、</span><span lang=EN-US>dup() </span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>、</span><span
lang=EN-US>fork() </span></span><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>、</span><span lang=EN-US>close</span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>、</span><span
lang=EN-US>execl() </span></span><span style='mso-bookmark:_Toc16587483'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>、</span><span lang=EN-US>exit</span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>，它们的功能分别是建立管道、复制文件描述符、创建进程并使子进程与父进程有相同的程序正文、关闭文件描述符、用指定文件覆盖调用程序、撤销当前进程。</span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt;font-family:黑体'><span
style='mso-spacerun:yes'> </span>清单4-5 pipeline.c<o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>// </span></span><span style='mso-bookmark:
_Toc16587483'><span style='font-size:9.0pt;font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>定义管道程序</span></span><span
style='mso-bookmark:_Toc16587483'><span lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p> </o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'># define STD_INPUT 0<span style='mso-tab-count:
4'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>定义标准输入设备描述符</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'># define STD_OUTPUT 1<span style='mso-tab-count:
4'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>定义标准输出设备描述符</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><o:p> </o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>int fd[2];<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><o:p> </o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>main()<o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>{<o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:45.0pt;mso-char-indent-count:5.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>static char
process1[]="father",process2[]="child";<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:1'> </span><span
style='mso-spacerun:yes'> </span>pipe(fd);<span
style='mso-tab-count:6'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>定义管道</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:1'> </span><span
style='mso-spacerun:yes'>
</span>pipeline(process1,process2);<span style='mso-tab-count:2'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>调用自定义函数</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>pipeline()<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:1'> </span><span
style='mso-spacerun:yes'> </span>exit(1);<span
style='mso-tab-count:6'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>程序结束</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>}<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><o:p> </o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>pipeline(char* process1,char* process2)<o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:27.0pt;mso-char-indent-count:3.0;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>{<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span
style='mso-spacerun:yes'>
</span>int i;<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:1'> </span><span
style='mso-spacerun:yes'> </span>while
((i=fork())==-1);<span style='mso-tab-count:3'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>创建进程，直到创建成功为止</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span
style='mso-spacerun:yes'>
</span>if (i)<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:1'> </span><span
style='mso-spacerun:yes'> </span>{<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:2'> </span><span
style='mso-spacerun:yes'> </span>close(fd[0]);<span
style='mso-tab-count:4'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>关闭管道输入描述符</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:2'> </span><span
style='mso-spacerun:yes'>
</span>close(STD_OUTPUT);<span style='mso-tab-count:2'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>关闭标准输出描述符</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>1<o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:2'> </span><span
style='mso-spacerun:yes'> </span>dup(fd[1]);<span
style='mso-tab-count:4'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>指定标准输出描述符</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>1</span></span><span style='mso-bookmark:
_Toc16587483'><span style='font-size:9.0pt;font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>为管道写指针</span></span><span
style='mso-bookmark:_Toc16587483'><span lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal><span style='mso-bookmark:_Toc16587483'><span lang=EN-US
style='font-size:9.0pt'><span style='mso-tab-count:2'> </span><span
style='mso-spacerun:yes'> </span>close(fd[1]);<span
style='mso-tab-count:4'> </span>//
</span></span><span style='mso-bookmark:_Toc16587483'><span style='font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>关闭原始管道写指针</span></span><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'><o:p></o:p></span></span></p>
<p class=MsoNormal style='text-indent:67.5pt;mso-char-indent-count:7.5;
mso-char-indent-size:9pt'><span style='mso-bookmark:_Toc16587483'><span
lang=EN-US style='font-size:9.0pt'>execl(process1, process1, 0);<span
style='mso-tab-count:1'> </span>// </span></span><span
style='mso-bookmark:_Toc16587483'><span style='font-size:9.0pt;font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>用程序</span></span><span
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