linux getopt函数分析命令行参数

Dear 丶 2022-03-01 12:54 217阅读 0赞

<table style="margin:0px; padding:0px; color:rgb(70,70,70); font-family:simsun; font-size:14px; text-align:left; background-color:rgb(220,220,220)"> 
 <tbody> 
  <tr> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> 
    <div> 
     <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">表头文件</span> 
    </div> </td> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">#include&lt;unistd.h&gt;<br> </span></td> 
  </tr> 
  <tr> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> 
    <div> 
     <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">定义函数</span> 
    </div> </td> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">int getopt(int argc,char * const argv[ ],const char * optstring);<br> </span></td> 
  </tr> 
  <tr> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> 
    <div> 
     <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">函数说明</span> 
    </div> </td> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">getopt()用来分析命令行参数。参数argc和argv是由main()传递的参数个数和内容。参数optstring 则代表欲处理的选项字符串。此函数会返回在argv 中下一个的选项字母，此字母会对应参数optstring 中的字母。如果选项字符串里的字母后接着冒号“:”，则表示还有相关的参数，全域变量optarg 即会指向此额外参数。如果getopt()找不到符合的参数则会印出错信息，并将全域变量optopt设为“?”字符，如果不希望getopt()印出错信息，则只要将全域变量opterr设为0即可。<br> </span></td> 
  </tr> 
  <tr> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> 
    <div> 
     <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">返回值</span> 
    </div> </td> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">如果找到符合的参数则返回此参数字母，如果参数不包含在参数optstring 的选项字母则返回“?”字符，分析结束则返回-1。<br> </span></td> 
  </tr> 
  <tr> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> 
    <div> 
     <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">范例</span> 
    </div> </td> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">#include&lt;stdio.h&gt;<br> #include&lt;unistd.h&gt;<br> int main(int argc,char **argv)<br> { <br> int ch;<br> opterr = 0;<br> while((ch = getopt(argc,argv,”a:bcde”))!= -1)<br> switch(ch)<br> { <br> case ‘a’:<br> printf(“option a:’%s’\n”,optarg);<br> break;<br> case ‘b’:<br> printf(“option b :b\n”);<br> break;<br> default:<br> printf(“other option :%c\n”,ch);<br> }<br> printf(“optopt +%c\n”,optopt);<br> }<br> </span></td> 
  </tr> 
  <tr> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> 
    <div> 
     <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">执行</span> 
    </div> </td> 
   <td style="margin:0px; padding:0px; font-family:Verdana,宋体,sans-serif; line-height:18px"> <span style="font-family:宋体; font-size:12px; word-wrap:normal; word-break:normal; line-height:19px">$./aaa –b<br> option b:b<br> $./aaa –c<br> other option:c<br> $./aaa –a<br> other option :?<br> $./aaa –a12345<br> option a:’12345’</span></td> 
  </tr> 
 </tbody> 
</table>