📄 posix线程编程指南(2).htm

📁 POSIX平台多线程编程指南通用开放式操作系统的多线程应用指南。
💻 HTM
📖 第 1 页 / 共 3 页
字号:
上一页 1 23
#define PTHREAD_KEY_1STLEVEL_SIZE   \
((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1)
/ PTHREAD_KEY_2NDLEVEL_SIZE)
    其中在/usr/include/bits/local_lim.h中定义了PTHREAD_KEYS_MAX为1024，因此一维数组大小为32。而具体存放的位置由key值经过以下计算得到：
idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE
idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE</CODE></PRE></TD></TR></TBODY></TABLE><BR>
            <P>也就是说，数据存放与一个32×32的稀疏矩阵中。同样，访问的时候也由key值经过类似计算得到数据所在位置索引，再取出其中内容返回。</P><BR>
            <TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
              <TBODY>
              <TR>
                <TD><IMG height=1 alt="" 
                  src="Posix线程编程指南(2).files/blue_rule.gif" width="100%"><BR><IMG 
                  height=6 alt="" src="Posix线程编程指南(2).files/c.gif" width=8 
                  border=0></TD></TR></TBODY></TABLE>
            <TABLE class=no-print cellSpacing=0 cellPadding=0 align=right>
              <TBODY>
              <TR align=right>
                <TD><IMG height=4 alt="" src="Posix线程编程指南(2).files/c.gif" 
                  width="100%"><BR>
                  <TABLE cellSpacing=0 cellPadding=0 border=0>
                    <TBODY>
                    <TR>
                      <TD vAlign=center><IMG height=16 alt="" 
                        src="Posix线程编程指南(2).files/u_bold.gif" width=16 
                        border=0><BR></TD>
                      <TD vAlign=top align=right><A class=fbox 
                        href="http://www-128.ibm.com/developerworks/cn/linux/thread/posix_threadapi/part2/#main"><B>回页首</B></A></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR><BR>
            <P><A name=4><SPAN class=atitle>使用范例</SPAN></A></P>
            <P>以下这个例子没有什么实际意义，只是说明如何使用，以及能够使用这一机制达到存储线程私有数据的目的。</P>
            <TABLE cellSpacing=0 cellPadding=5 width="100%" bgColor=#eeeeee 
            border=1>
              <TBODY>
              <TR>
                <TD><PRE><CODE class=section>#include &lt;stdio.h&gt;
#include &lt;pthread.h&gt;

pthread_key_t   key;

void echomsg(int t)
{
        printf("destructor excuted in thread %d,param=%d\n",pthread_self(),t);
}

void * child1(void *arg)
{
        int tid=pthread_self();
        printf("thread %d enter\n",tid);
        pthread_setspecific(key,(void *)tid);
        sleep(2);
        printf("thread %d returns %d\n",tid,pthread_getspecific(key));
        sleep(5);
}

void * child2(void *arg)
{
        int tid=pthread_self();
        printf("thread %d enter\n",tid);
        pthread_setspecific(key,(void *)tid);
        sleep(1);
        printf("thread %d returns %d\n",tid,pthread_getspecific(key));
        sleep(5);
}

int main(void)
{
        int tid1,tid2;

        printf("hello\n");
        pthread_key_create(&amp;key,echomsg);
        pthread_create(&amp;tid1,NULL,child1,NULL);
        pthread_create(&amp;tid2,NULL,child2,NULL);
        sleep(10);
        pthread_key_delete(key);
        printf("main thread exit\n");
        return 0;
}</CODE></PRE></TD></TR></TBODY></TABLE><BR>
            <P>给例程创建两个线程分别设置同一个线程私有数据为自己的线程ID，为了检验其私有性，程序错开了两个线程私有数据的写入和读出的时间，从程序运行结果可以看出，两个线程对TSD的修改互不干扰。同时，当线程退出时，清理函数会自动执行，参数为tid。</P><BR>
            <TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
              <TBODY>
              <TR>
                <TD><IMG height=1 alt="" 
                  src="Posix线程编程指南(2).files/blue_rule.gif" width="100%"><BR><IMG 
                  height=6 alt="" src="Posix线程编程指南(2).files/c.gif" width=8 
                  border=0></TD></TR></TBODY></TABLE>
            <TABLE class=no-print cellSpacing=0 cellPadding=0 align=right>
              <TBODY>
              <TR align=right>
                <TD><IMG height=4 alt="" src="Posix线程编程指南(2).files/c.gif" 
                  width="100%"><BR>
                  <TABLE cellSpacing=0 cellPadding=0 border=0>
                    <TBODY>
                    <TR>
                      <TD vAlign=center><IMG height=16 alt="" 
                        src="Posix线程编程指南(2).files/u_bold.gif" width=16 
                        border=0><BR></TD>
                      <TD vAlign=top align=right><A class=fbox 
                        href="http://www-128.ibm.com/developerworks/cn/linux/thread/posix_threadapi/part2/#main"><B>回页首</B></A></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR><BR><BR>
            <TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
              <TBODY>
              <TR>
                <TD><IMG height=1 alt="" 
                  src="Posix线程编程指南(2).files/blue_rule.gif" width="100%"><BR><IMG 
                  height=6 alt="" src="Posix线程编程指南(2).files/c.gif" width=8 
                  border=0></TD></TR></TBODY></TABLE>
            <TABLE class=no-print cellSpacing=0 cellPadding=0 align=right>
              <TBODY>
              <TR align=right>
                <TD><IMG height=4 alt="" src="Posix线程编程指南(2).files/c.gif" 
                  width="100%"><BR>
                  <TABLE cellSpacing=0 cellPadding=0 border=0>
                    <TBODY>
                    <TR>
                      <TD vAlign=center><IMG height=16 alt="" 
                        src="Posix线程编程指南(2).files/u_bold.gif" width=16 
                        border=0><BR></TD>
                      <TD vAlign=top align=right><A class=fbox 
                        href="http://www-128.ibm.com/developerworks/cn/linux/thread/posix_threadapi/part2/#main"><B>回页首</B></A></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR><BR>
            <P><A name=author><SPAN class=atitle>关于作者</SPAN></A></P>
            <TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
              <TBODY>
              <TR>
                <TD colSpan=3><IMG height=5 alt="" 
                  src="Posix线程编程指南(2).files/c.gif" width="100%"></TD></TR>
              <TR vAlign=top align=left>
                <TD>
                  <P></P></TD>
                <TD><IMG height=5 alt="" src="Posix线程编程指南(2).files/c.gif" 
                  width=4></TD>
                <TD width="100%">
                  <P><B>杨沙洲，</B>男，现攻读国防科大计算机学院计算机软件方向博士学位。您可以通过电子邮件 <A 
                  href="mailto:pubb@163.net">pubb@163.net</A>跟他联系。 
              </P></TD></TR></TBODY></TABLE><BR><BR>
            <TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
              <TBODY>
              <TR>
                <TD><IMG height=1 alt="" 
                  src="Posix线程编程指南(2).files/blue_rule.gif" width="100%"><BR><IMG 
                  height=6 alt="" src="Posix线程编程指南(2).files/c.gif" width=8 
                  border=0></TD></TR></TBODY></TABLE>
            <TABLE class=no-print cellSpacing=0 cellPadding=0 align=right>
              <TBODY>
              <TR align=right>
                <TD><IMG height=4 alt="" src="Posix线程编程指南(2).files/c.gif" 
                  width="100%"><BR>
                  <TABLE cellSpacing=0 cellPadding=0 border=0>
                    <TBODY>
                    <TR>
                      <TD vAlign=center><IMG height=16 alt="" 
                        src="Posix线程编程指南(2).files/u_bold.gif" width=16 
                        border=0><BR></TD>
                      <TD vAlign=top align=right><A class=fbox 
                        href="http://www-128.ibm.com/developerworks/cn/linux/thread/posix_threadapi/part2/#main"><B>回页首</B></A></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR><BR>
            <P class=no-print><SPAN class=atitle><A 
            name=rate>对本文的评价</A></SPAN></P><SPAN class=no-print>
            <TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
              <TBODY>
              <TR vAlign=top>
                <TD>
                  <FORM 
                  action=https://www-128.ibm.com/developerworks/secure/cnratings.jsp 
                  method=get><INPUT type=hidden value=Posix线程编程指南(2) 
                  name=ArticleTitle><INPUT type=hidden value=Linux 
                  name=Zone><INPUT type=hidden 
                  value=http://www.ibm.com/developerworks/cn/thankyou/ 
                  name=RedirectURL><INPUT type=hidden value=china 
name=localsite>
                  <SCRIPT language=javascript>document.write('<input type="hidden" name="url" value="'+location.href+'">');</SCRIPT>

                  <TABLE cellSpacing=0 cellPadding=0 border=0>
                    <TBODY>
                    <TR>
                      <TD><IMG height=8 alt="" 
                        src="Posix线程编程指南(2).files/c.gif" width=100 
                    border=0></TD></TR>
                    <TR vAlign=top>
                      <TD><INPUT type=radio value=1 name=Rating>太差！ (1)</TD></TR>
                    <TR vAlign=top>
                      <TD><INPUT type=radio value=2 name=Rating>需提高 (2)</TD></TR>
                    <TR vAlign=top>
                      <TD><INPUT type=radio value=3 name=Rating>一般；尚可 
(3)</TD></TR>
                    <TR vAlign=top>
                      <TD><INPUT type=radio value=4 name=Rating>好文章 (4)</TD></TR>
                    <TR vAlign=top>
                      <TD><INPUT type=radio value=5 
                    name=Rating>真棒！(5)</TD></TR></TBODY></TABLE><BR><B>建议？</B><BR><TEXTAREA id=Comments name=Comments rows=5 wrap=virtual cols=60>&nbsp;</TEXTAREA><BR><BR><INPUT type=submit value=反馈意见></FORM></TD></TR>
              <TR vAlign=top>
                <TD bgColor=#ffffff><IMG height=8 alt="" 
                  src="Posix线程编程指南(2).files/c.gif" width=100 
              border=0></TD></TR></TBODY></TABLE></SPAN><SPAN class=no-print>
            <TABLE cellSpacing=0 cellPadding=0 align=right>
              <TBODY>
              <TR align=right>
                <TD><IMG height=8 alt="" src="Posix线程编程指南(2).files/c.gif" 
                  width="100%"><BR>
                  <TABLE cellSpacing=0 cellPadding=0 border=0>
                    <TBODY>
                    <TR>
                      <TD vAlign=center><IMG height=16 alt="" 
                        src="Posix线程编程指南(2).files/u_bold.gif" width=16 
                        border=0><BR></TD>
                      <TD vAlign=top align=right><A class=fbox 
                        href="http://www-128.ibm.com/developerworks/cn/linux/thread/posix_threadapi/part2/#main"><B>回页首</B></A></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE><BR><BR></SPAN></TD>
          <TD width=10><IMG height=1 alt="" src="Posix线程编程指南(2).files/c.gif" 
            width=10></TD></TR></TBODY></TABLE>
      <P class=greytext>其他公司、产品或服务的名称可能是其他公司的商标或服务标志。</P></TD></TR></TBODY></TABLE><!--FOOTER_BEGIN--><BR>
<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
  <TBODY>
  <TR>
    <TD class=bbg height=19>
      <TABLE cellSpacing=0 cellPadding=0 border=0>
        <TBODY>
        <TR>
          <TD><SPAN class=spacer>&nbsp;&nbsp;&nbsp;&nbsp;</SPAN><A 
            class=mainlink href="http://www.ibm.com/cn/ibm/index.shtml">关于 
            IBM</A></TD>
          <TD class=footer-divider width=27>&nbsp;&nbsp;&nbsp;&nbsp;</TD>
          <TD><A class=mainlink 
            href="http://www.ibm.com/cn/ibm/privacy/index.shtml">隐私条约</A></TD>
          <TD class=footer-divider width=27>&nbsp;&nbsp;&nbsp;&nbsp;</TD>
          <TD><A class=mainlink href="http://www.ibm.com/contact/">联系 
          IBM</A></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
<SCRIPT language=JavaScript1.2 src="Posix线程编程指南(2).files/stats.js" 
type=text/javascript></SCRIPT>
<NOSCRIPT><IMG height=1 alt="" 
src="E:\MyLove\资料\Posix线程编程指南\Posix线程编程指南(2).files\c(1).gif" width=1 
border=0></NOSCRIPT><!--FOOTER_END--><!--XSLT stylesheet used to transform this file:  dw-document-html-5.3.xsl--> 
</BODY></HTML>
上一页 1 23
⌨️ 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 + -