C++博客-那谁的技术博客-随笔分类-Linux/Unixhttp://www.cppblog.com/converse/category/3799.html感兴趣领域:高性能服务器编程,算法,Linux内核zh-cnTue, 08 Dec 2009 05:09:54 GMTTue, 08 Dec 2009 05:09:54 GMT60带超时机制的DNS解析APIhttp://www.cppblog.com/converse/archive/2009/11/07/100349.html那谁那谁Sat, 07 Nov 2009 11:28:00 GMThttp://www.cppblog.com/converse/archive/2009/11/07/100349.htmlhttp://www.cppblog.com/converse/comments/100349.htmlhttp://www.cppblog.com/converse/archive/2009/11/07/100349.html#Feedback2http://www.cppblog.com/converse/comments/commentRss/100349.htmlhttp://www.cppblog.com/converse/services/trackbacks/100349.html阅读全文

那谁 2009-11-07 19:28 发表评论
]]>同步/异步与阻塞/非阻塞的区别http://www.cppblog.com/converse/archive/2009/05/13/82879.html那谁那谁Wed, 13 May 2009 14:11:00 GMThttp://www.cppblog.com/converse/archive/2009/05/13/82879.htmlhttp://www.cppblog.com/converse/comments/82879.htmlhttp://www.cppblog.com/converse/archive/2009/05/13/82879.html#Feedback12http://www.cppblog.com/converse/comments/commentRss/82879.htmlhttp://www.cppblog.com/converse/services/trackbacks/82879.html阅读全文

那谁 2009-05-13 22:11 发表评论
]]>connect的两种出错情况http://www.cppblog.com/converse/archive/2009/04/23/80889.html那谁那谁Thu, 23 Apr 2009 12:43:00 GMThttp://www.cppblog.com/converse/archive/2009/04/23/80889.htmlhttp://www.cppblog.com/converse/comments/80889.htmlhttp://www.cppblog.com/converse/archive/2009/04/23/80889.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/80889.htmlhttp://www.cppblog.com/converse/services/trackbacks/80889.html阅读全文

那谁 2009-04-23 20:43 发表评论
]]>linux内核V2.6.11学习笔记(2)--list和hlisthttp://www.cppblog.com/converse/archive/2009/04/11/79572.html那谁那谁Sat, 11 Apr 2009 02:47:00 GMThttp://www.cppblog.com/converse/archive/2009/04/11/79572.htmlhttp://www.cppblog.com/converse/comments/79572.htmlhttp://www.cppblog.com/converse/archive/2009/04/11/79572.html#Feedback8http://www.cppblog.com/converse/comments/commentRss/79572.htmlhttp://www.cppblog.com/converse/services/trackbacks/79572.html阅读全文

那谁 2009-04-11 10:47 发表评论
]]>linux内核V2.6.11学习笔记(1)--pid位图http://www.cppblog.com/converse/archive/2009/04/10/79488.html那谁那谁Fri, 10 Apr 2009 04:57:00 GMThttp://www.cppblog.com/converse/archive/2009/04/10/79488.htmlhttp://www.cppblog.com/converse/comments/79488.htmlhttp://www.cppblog.com/converse/archive/2009/04/10/79488.html#Feedback6http://www.cppblog.com/converse/comments/commentRss/79488.htmlhttp://www.cppblog.com/converse/services/trackbacks/79488.html阅读全文

那谁 2009-04-10 12:57 发表评论
]]>memcached内存管理算法http://www.cppblog.com/converse/archive/2009/03/09/76037.html那谁那谁Mon, 09 Mar 2009 14:24:00 GMThttp://www.cppblog.com/converse/archive/2009/03/09/76037.htmlhttp://www.cppblog.com/converse/comments/76037.htmlhttp://www.cppblog.com/converse/archive/2009/03/09/76037.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/76037.htmlhttp://www.cppblog.com/converse/services/trackbacks/76037.html阅读全文

那谁 2009-03-09 22:24 发表评论
]]>我的项目Makefile文件模板http://www.cppblog.com/converse/archive/2009/02/23/74716.html那谁那谁Mon, 23 Feb 2009 14:55:00 GMThttp://www.cppblog.com/converse/archive/2009/02/23/74716.htmlhttp://www.cppblog.com/converse/comments/74716.htmlhttp://www.cppblog.com/converse/archive/2009/02/23/74716.html#Feedback7http://www.cppblog.com/converse/comments/commentRss/74716.htmlhttp://www.cppblog.com/converse/services/trackbacks/74716.html阅读全文

那谁 2009-02-23 22:55 发表评论
]]>Linux下面的线程锁,条件变量以及信号量的使用http://www.cppblog.com/converse/archive/2009/01/15/72064.html那谁那谁Thu, 15 Jan 2009 02:23:00 GMThttp://www.cppblog.com/converse/archive/2009/01/15/72064.htmlhttp://www.cppblog.com/converse/comments/72064.htmlhttp://www.cppblog.com/converse/archive/2009/01/15/72064.html#Feedback2http://www.cppblog.com/converse/comments/commentRss/72064.htmlhttp://www.cppblog.com/converse/services/trackbacks/72064.html阅读全文

那谁 2009-01-15 10:23 发表评论
]]>对一个服务器的几步优化http://www.cppblog.com/converse/archive/2008/10/22/64733.html那谁那谁Wed, 22 Oct 2008 12:10:00 GMThttp://www.cppblog.com/converse/archive/2008/10/22/64733.htmlhttp://www.cppblog.com/converse/comments/64733.htmlhttp://www.cppblog.com/converse/archive/2008/10/22/64733.html#Feedback18http://www.cppblog.com/converse/comments/commentRss/64733.htmlhttp://www.cppblog.com/converse/services/trackbacks/64733.html阅读全文

那谁 2008-10-22 20:10 发表评论
]]>服务器定时器处理要注意的问题http://www.cppblog.com/converse/archive/2008/10/16/64187.html那谁那谁Thu, 16 Oct 2008 11:08:00 GMThttp://www.cppblog.com/converse/archive/2008/10/16/64187.htmlhttp://www.cppblog.com/converse/comments/64187.htmlhttp://www.cppblog.com/converse/archive/2008/10/16/64187.html#Feedback7http://www.cppblog.com/converse/comments/commentRss/64187.htmlhttp://www.cppblog.com/converse/services/trackbacks/64187.html阅读全文

那谁 2008-10-16 19:08 发表评论
]]>epoll相关资料整理http://www.cppblog.com/converse/archive/2008/10/13/63928.html那谁那谁Mon, 13 Oct 2008 14:11:00 GMThttp://www.cppblog.com/converse/archive/2008/10/13/63928.htmlhttp://www.cppblog.com/converse/comments/63928.htmlhttp://www.cppblog.com/converse/archive/2008/10/13/63928.html#Feedback2http://www.cppblog.com/converse/comments/commentRss/63928.htmlhttp://www.cppblog.com/converse/services/trackbacks/63928.html阅读全文

那谁 2008-10-13 22:11 发表评论
]]>epoll为什么这么快http://www.cppblog.com/converse/archive/2008/10/12/63836.html那谁那谁Sun, 12 Oct 2008 14:35:00 GMThttp://www.cppblog.com/converse/archive/2008/10/12/63836.htmlhttp://www.cppblog.com/converse/comments/63836.htmlhttp://www.cppblog.com/converse/archive/2008/10/12/63836.html#Feedback6http://www.cppblog.com/converse/comments/commentRss/63836.htmlhttp://www.cppblog.com/converse/services/trackbacks/63836.html阅读全文

那谁 2008-10-12 22:35 发表评论
]]>lighttpd1.4.18代码分析(八)--状态机(2)CON_STATE_READ状态http://www.cppblog.com/converse/archive/2008/09/24/62658.html那谁那谁Wed, 24 Sep 2008 02:50:00 GMThttp://www.cppblog.com/converse/archive/2008/09/24/62658.htmlhttp://www.cppblog.com/converse/comments/62658.htmlhttp://www.cppblog.com/converse/archive/2008/09/24/62658.html#Feedback1http://www.cppblog.com/converse/comments/commentRss/62658.htmlhttp://www.cppblog.com/converse/services/trackbacks/62658.html阅读全文

那谁 2008-09-24 10:50 发表评论
]]>lighttpd1.4.18代码分析(七)--状态机(1)CON_STATE_REQUEST_START状态http://www.cppblog.com/converse/archive/2008/09/22/62497.html那谁那谁Mon, 22 Sep 2008 07:10:00 GMThttp://www.cppblog.com/converse/archive/2008/09/22/62497.htmlhttp://www.cppblog.com/converse/comments/62497.htmlhttp://www.cppblog.com/converse/archive/2008/09/22/62497.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/62497.htmlhttp://www.cppblog.com/converse/services/trackbacks/62497.html阅读全文

那谁 2008-09-22 15:10 发表评论
]]>lighttpd1.4.18代码分析(六)--处理连接fd的流程http://www.cppblog.com/converse/archive/2008/09/19/62252.html那谁那谁Fri, 19 Sep 2008 02:46:00 GMThttp://www.cppblog.com/converse/archive/2008/09/19/62252.htmlhttp://www.cppblog.com/converse/comments/62252.htmlhttp://www.cppblog.com/converse/archive/2008/09/19/62252.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/62252.htmlhttp://www.cppblog.com/converse/services/trackbacks/62252.html阅读全文

那谁 2008-09-19 10:46 发表评论
]]>lighttpd1.4.18代码分析(五)--处理超时连接http://www.cppblog.com/converse/archive/2008/09/05/61039.html那谁那谁Fri, 05 Sep 2008 11:33:00 GMThttp://www.cppblog.com/converse/archive/2008/09/05/61039.htmlhttp://www.cppblog.com/converse/comments/61039.htmlhttp://www.cppblog.com/converse/archive/2008/09/05/61039.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/61039.htmlhttp://www.cppblog.com/converse/services/trackbacks/61039.html阅读全文

那谁 2008-09-05 19:33 发表评论
]]>lighttpd1.4.18代码分析(四)--处理监听fd的流程http://www.cppblog.com/converse/archive/2008/09/03/60798.html那谁那谁Wed, 03 Sep 2008 03:17:00 GMThttp://www.cppblog.com/converse/archive/2008/09/03/60798.htmlhttp://www.cppblog.com/converse/comments/60798.htmlhttp://www.cppblog.com/converse/archive/2008/09/03/60798.html#Feedback2http://www.cppblog.com/converse/comments/commentRss/60798.htmlhttp://www.cppblog.com/converse/services/trackbacks/60798.html阅读全文

那谁 2008-09-03 11:17 发表评论
]]>APUE2读书笔记(三):不可重入函数http://www.cppblog.com/converse/archive/2008/09/02/60712.html那谁那谁Tue, 02 Sep 2008 09:18:00 GMThttp://www.cppblog.com/converse/archive/2008/09/02/60712.htmlhttp://www.cppblog.com/converse/comments/60712.htmlhttp://www.cppblog.com/converse/archive/2008/09/02/60712.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/60712.htmlhttp://www.cppblog.com/converse/services/trackbacks/60712.html阅读全文

那谁 2008-09-02 17:18 发表评论
]]>lighttpd1.4.18代码分析(三)--网络IO事件处理器的使用http://www.cppblog.com/converse/archive/2008/08/28/60305.html那谁那谁Thu, 28 Aug 2008 15:20:00 GMThttp://www.cppblog.com/converse/archive/2008/08/28/60305.htmlhttp://www.cppblog.com/converse/comments/60305.htmlhttp://www.cppblog.com/converse/archive/2008/08/28/60305.html#Feedback2http://www.cppblog.com/converse/comments/commentRss/60305.htmlhttp://www.cppblog.com/converse/services/trackbacks/60305.html阅读全文

那谁 2008-08-28 23:20 发表评论
]]>lighttpd1.4.18代码分析(二)--fdevents结构体解析http://www.cppblog.com/converse/archive/2008/08/25/59920.html那谁那谁Mon, 25 Aug 2008 08:10:00 GMThttp://www.cppblog.com/converse/archive/2008/08/25/59920.htmlhttp://www.cppblog.com/converse/comments/59920.htmlhttp://www.cppblog.com/converse/archive/2008/08/25/59920.html#Feedback4http://www.cppblog.com/converse/comments/commentRss/59920.htmlhttp://www.cppblog.com/converse/services/trackbacks/59920.html阅读全文

那谁 2008-08-25 16:10 发表评论
]]>lighttpd1.4.18代码分析(一)--watcher,worker模型http://www.cppblog.com/converse/archive/2008/08/22/59683.html那谁那谁Fri, 22 Aug 2008 12:18:00 GMThttp://www.cppblog.com/converse/archive/2008/08/22/59683.htmlhttp://www.cppblog.com/converse/comments/59683.htmlhttp://www.cppblog.com/converse/archive/2008/08/22/59683.html#Feedback5http://www.cppblog.com/converse/comments/commentRss/59683.htmlhttp://www.cppblog.com/converse/services/trackbacks/59683.html阅读全文

那谁 2008-08-22 20:18 发表评论
]]>Unix Toolboxhttp://www.cppblog.com/converse/archive/2008/08/20/59422.html那谁那谁Wed, 20 Aug 2008 03:18:00 GMThttp://www.cppblog.com/converse/archive/2008/08/20/59422.htmlhttp://www.cppblog.com/converse/comments/59422.htmlhttp://www.cppblog.com/converse/archive/2008/08/20/59422.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/59422.htmlhttp://www.cppblog.com/converse/services/trackbacks/59422.html阅读全文

那谁 2008-08-20 11:18 发表评论
]]>服务器公共库开发--定时器管理器模块http://www.cppblog.com/converse/archive/2008/08/13/58731.html那谁那谁Wed, 13 Aug 2008 07:36:00 GMThttp://www.cppblog.com/converse/archive/2008/08/13/58731.htmlhttp://www.cppblog.com/converse/comments/58731.htmlhttp://www.cppblog.com/converse/archive/2008/08/13/58731.html#Feedback2http://www.cppblog.com/converse/comments/commentRss/58731.htmlhttp://www.cppblog.com/converse/services/trackbacks/58731.html阅读全文

那谁 2008-08-13 15:36 发表评论
]]>服务器公共库开发-内存池管理模块http://www.cppblog.com/converse/archive/2008/08/11/58563.html那谁那谁Mon, 11 Aug 2008 15:30:00 GMThttp://www.cppblog.com/converse/archive/2008/08/11/58563.htmlhttp://www.cppblog.com/converse/comments/58563.htmlhttp://www.cppblog.com/converse/archive/2008/08/11/58563.html#Feedback14http://www.cppblog.com/converse/comments/commentRss/58563.htmlhttp://www.cppblog.com/converse/services/trackbacks/58563.html阅读全文

那谁 2008-08-11 23:30 发表评论
]]>ccache发布0.3版本http://www.cppblog.com/converse/archive/2008/08/07/58253.html那谁那谁Thu, 07 Aug 2008 09:27:00 GMThttp://www.cppblog.com/converse/archive/2008/08/07/58253.htmlhttp://www.cppblog.com/converse/comments/58253.htmlhttp://www.cppblog.com/converse/archive/2008/08/07/58253.html#Feedback2http://www.cppblog.com/converse/comments/commentRss/58253.htmlhttp://www.cppblog.com/converse/services/trackbacks/58253.html阅读全文

那谁 2008-08-07 17:27 发表评论
]]>服务器公共库开发--log系统http://www.cppblog.com/converse/archive/2008/08/05/58044.html那谁那谁Tue, 05 Aug 2008 03:37:00 GMThttp://www.cppblog.com/converse/archive/2008/08/05/58044.htmlhttp://www.cppblog.com/converse/comments/58044.htmlhttp://www.cppblog.com/converse/archive/2008/08/05/58044.html#Feedback10http://www.cppblog.com/converse/comments/commentRss/58044.htmlhttp://www.cppblog.com/converse/services/trackbacks/58044.html阅读全文

那谁 2008-08-05 11:37 发表评论
]]>linux下面nc的使用http://www.cppblog.com/converse/archive/2008/07/20/56687.html那谁那谁Sun, 20 Jul 2008 08:53:00 GMThttp://www.cppblog.com/converse/archive/2008/07/20/56687.htmlhttp://www.cppblog.com/converse/comments/56687.htmlhttp://www.cppblog.com/converse/archive/2008/07/20/56687.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/56687.htmlhttp://www.cppblog.com/converse/services/trackbacks/56687.html阅读全文

那谁 2008-07-20 16:53 发表评论
]]>epoll学习笔记http://www.cppblog.com/converse/archive/2008/04/29/48482.html那谁那谁Tue, 29 Apr 2008 12:06:00 GMThttp://www.cppblog.com/converse/archive/2008/04/29/48482.htmlhttp://www.cppblog.com/converse/comments/48482.htmlhttp://www.cppblog.com/converse/archive/2008/04/29/48482.html#Feedback19http://www.cppblog.com/converse/comments/commentRss/48482.htmlhttp://www.cppblog.com/converse/services/trackbacks/48482.html阅读全文

那谁 2008-04-29 20:06 发表评论
]]>发布我的开源cache库ccachehttp://www.cppblog.com/converse/archive/2008/03/24/45236.html那谁那谁Mon, 24 Mar 2008 03:20:00 GMThttp://www.cppblog.com/converse/archive/2008/03/24/45236.htmlhttp://www.cppblog.com/converse/comments/45236.htmlhttp://www.cppblog.com/converse/archive/2008/03/24/45236.html#Feedback8http://www.cppblog.com/converse/comments/commentRss/45236.htmlhttp://www.cppblog.com/converse/services/trackbacks/45236.html阅读全文

那谁 2008-03-24 11:20 发表评论
]]>APUE2读书笔记(二):为什么有了wait函数族还需要SIGCHLD信号http://www.cppblog.com/converse/archive/2007/12/28/39870.html那谁那谁Fri, 28 Dec 2007 15:39:00 GMThttp://www.cppblog.com/converse/archive/2007/12/28/39870.htmlhttp://www.cppblog.com/converse/comments/39870.htmlhttp://www.cppblog.com/converse/archive/2007/12/28/39870.html#Feedback0http://www.cppblog.com/converse/comments/commentRss/39870.htmlhttp://www.cppblog.com/converse/services/trackbacks/39870.htmlIn UNIX System terminology, a process that has terminated, but whose parent has not yet waited for it, is called a zombie.
也就是说,但凡是父进程没有调用wait函数获得子进程终止状态的子进程在终止之后都是僵尸进程,这个概念的关键一点就是父进程是否调用了wait函数.

而关于SIGCHLD信号,APUE2中又如是说:
Whenever a process terminates or stops, the SIGCHLD signal is sent to the parent. By default, this signal is ignored, so the parent must catch this signal if it wants to be notified whenever a child's status changes. The normal action in the signal-catching function is to call one of the wait functions to fetch the child's process ID and termination status.
简单的说,子进程退出时父进程会收到一个SIGCHLD信号,默认的处理是忽略这个信号,而常规的做法是在这个信号处理函数中调用wait函数获取子进程的退出状态.

这里存在一个疑问,既然在SIGCHLD信号的处理函数中要调用wait函数族,为什么有了wait函数族还需要使用SIGCHLD信号?

我们知道,unix中信号是异步处理某事的机制,好比说你准备去做某事,去之前跟邻居张三说如果李四来找你的话就通知他一声,这让你可以抽身出来去做这件事,而李四真正来访时会有人通知你,这个就是异步信号一个较为形象的比喻.

一般的,父进程在生成子进程之后会有两种情况,一种是父进程继续去做别的事情,类似上面举的例子,另一种是父进程啥都不做,一直在wait子进程退出.SIGCHLD信号就是为这第一种情况准备的,它让父进程去做别的事情,而只要父进程注册了处理该信号的函数,在子进程退出时就会调用该函数,在函数中wait子进程得到终止状态之后再继续做父进程的事情.

也就是说,明确以下几点:
1)凡父进程不调用wait函数族获得子进程终止状态的子进程在退出时都会变成僵尸进程.
2)SIGCHLD信号可以异步的通知父进程有子进程退出.


那谁 2007-12-28 23:39 发表评论
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