blocks|key|4555643|text|您没有详细说明您正在使用哪种语言进行开发，但是既然您提到了system()，我想您指的是C或C%2B%2B。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4555644|通常，这是通过使用fcntl()在不希望继承的那些文件描述符上设置close-+on+-exec标志来实现的：|4555645|int+fd+=+open("somefile",+O_RDONLY);
fcntl(fd,+F_SETFD,+FD_CLOEXEC);|code-block|syntax|javascript|4555646|你也可以在fork之后但在exec之前，通过对子进程中所有可能的fd进行迭代，以蛮力的方式来实现。这有点棘手，因为它要求你知道最大可能的fd值是多少，而且效率也较低，因为你最终会迭代并“关闭”一堆未使用的fd。|4555647|pid_t+pid+=+fork();
switch+(pid)+{
++++case+0:
++++++++//+In+the+child+process.++Iterate+through+all+possible+file+descriptors
++++++++//+and+explicitly+close+them.

++++++++long+maxfd+=+sysconf(OPEN_MAX);
++++++++for+(long+i+=+0;+i+<+maxfd;+%2B%2Bi)+{
++++++++++++close(i);
++++++++}

++++++++//+Now+exec+the+new+program,+file-handle+free.

++++++++execlp("someprogram",+"arg1",+"arg2");
++++++++break;
++++case+-1:
++++++++//+TODO:+handle+errors.

++++++++break;
++++default:
++++++++//+Parent+process.

++++++++int+status;
++++++++pid_t+finished+=+waitpid(pid,+&status,+0);
++++++++break;
}|4555648|希望这能有所帮助，|4555649|埃里克·梅尔斯基|4555650|entityMap^0|T|8|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|11|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|13|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|14|8|@]|D|@]|E|$]]|$1|U|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|V|$]]

You didn't specify what language you are developing in, but since you mentioned <code>system()</code>, I assume you mean C or C++.

Typically this is accomplished by using fcntl() to set the close-on-exec flag on those file descriptors that you do not want to be inherited:

<pre><code>int fd = open("somefile", O_RDONLY);
fcntl(fd, F_SETFD, FD_CLOEXEC);
</code></pre>

You could also do it the brute force way by iterating through all possible fd's in the child process after you fork but before you exec. This is a bit trickier because it requires that you know what the maximum possible fd value is, and it is also less efficient because you'll end up iterating through and "closing" a bunch of unused fd's. Something like this:

<pre><code>pid_t pid = fork();
switch (pid) {
 case 0:
 // In the child process. Iterate through all possible file descriptors
 // and explicitly close them.

 long maxfd = sysconf(OPEN_MAX);
 for (long i = 0; i &lt; maxfd; ++i) {
 close(i);
 }

 // Now exec the new program, file-handle free.

 execlp("someprogram", "arg1", "arg2");
 break;
 case -1:
 // TODO: handle errors.

 break;
 default:
 // Parent process.

 int status;
 pid_t finished = waitpid(pid, &amp;status, 0);
 break;
}
</code></pre>

Hope that helps,

Eric Melski

blocks|key|1532857|text|在Mac上，您可以使用使用opendir()/readdir()读取目录/dev/fd/来确定打开的文件描述符的集合。有了这些信息，您可以对每个打开的文件描述符调用fcntl(fd,+F_SETFD,+FD_CLOEXEC)，或者在派生之后对每个文件描述符调用close(fd)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1532858|有关其他详细信息，请参阅Getting+the+highest+allocated+file+descriptor，包括其他系统的方法。|1532859|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/899038/getting-the-highest-allocated-file-descriptor/918469#918469^0|D|9|N|9|10|8|2A|6|2I|M|3M|6|3U|1|0|C|19|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]|$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|14|8|@]|D|@$9|15|A|16|1|17]]|E|$]]|$1|H|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

On Mac OS X you can use read the directory <code>/dev/fd/</code> with <code>opendir()</code>/<code>readdir()</code> to determine the set of open file descriptors. With this information you can either call <code>fcntl(</code>fd<code>, F_SETFD, FD_CLOEXEC)</code> on each open file descriptor, or alternatively you could call <code>close(</code>fd<code>)</code> on each file descriptor after forking.

See <a href="https://stackoverflow.com/questions/899038/getting-the-highest-allocated-file-descriptor/918469#918469">Getting the highest allocated file descriptor</a> for some additional details, including approaches for other systems.

blocks|key|4555752|text|经过一些实验，我发现Mac上的'open‘shell命令创建了一个不继承父文件/端口的进程。调用'open+foo.app‘作为系统函数的参数可以解决这个问题。当然，这只是mac。对于Unix，这里建议的另一种方法很有意义。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4555753|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

After some experimenting, I found that the 'open' shell command on Mac creates a process that does not inherit the parents files/ports. Invoking 'open foo.app' as arguments to the system function does the trick. Of course, this is mac only. For Unix, one of the other approaches suggested here makes a lot of sense.

blocks|key|233296|text|@Eric+M:你的回答让我走了大部分路，但我发现它仍然有一些文件描述符是打开的。我用getdtablesize()替换了上面代码中的sysconf(OPEN_MAX)，它工作得很好。谢谢你的帮助！|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|233297|entityMap^0|17|F|1V|H|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

@Eric M: Your answer got me most of the way there, but I found that it still left some file descriptors open. I replaced <code>sysconf(OPEN_MAX)</code> in your code above with <code>getdtablesize()</code> and it works great. Thanks for the help!

I want to launch a child process on OS X such that the child process does not inherit the current process's open files/ports. 

Any suggestions on how to accomplish this? Shell commands that I can invoke using the system() function would work too - I just don't know of a good shell command that enables this.

Thanks!

Launch a child process on OSX/Unix that doesn't inherit files/ports

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

我想在OS X上启动子进程，这样子进程就不会继承当前进程的打开文件/端口。对如何实现这一点有什么建议吗？我可以使用system()函数调用的Shell命令也可以工作--我只是不知道有什么好的shell命令可以实现这一点。谢谢!

问在OSX/Unix上启动一个不继承文件/端口的子进程
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在OSX/Unix上启动一个不继承文件/端口的子进程EN