不熟悉的 Linux API

最新推荐文章于 2025-10-30 10:33:56 发布

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本文介绍了如何使用daemon函数创建后台进程并从终端分离，以及如何通过sched_setscheduler和sched_getscheduler来设置和获取进程调度策略。

1. daemon

#inlcude <unistd.h>

int daemon(int nochdir, int noclose);

    The daemon() function is for programs wishing to detach themselves from the controlling terminal and run in the background as system daemons.

       If nochdir is zero, daemon() changes the calling process's current
       working directory to the root directory ("/"); otherwise, the current
       working directory is left unchanged.

       If noclose is zero, daemon() redirects standard input, standard
       output and standard error to /dev/null; otherwise, no changes are
       made to these file descriptors.

(This function forks, and if the fork(2) succeeds, the parent calls
       _exit(2), so that further errors are seen by the child only.)  On
       success daemon() returns zero.  If an error occurs, daemon() returns
       -1 and sets errno to any of the errors specified for the fork(2) and
       setsid(2).