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DAEMON(3)                  Linux Programmer's Manual                 DAEMON(3)



NAME
       daemon - run in the background

SYNOPSIS
       #include <unistd.h>

       int daemon(int nochdir, int noclose);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       daemon(): _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

DESCRIPTION
       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 process's current working directory to the root directory ("/");  oth-
       erwise,

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

RETURN VALUE
       (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).

CONFORMING TO
       Not in POSIX.1-2001.  A similar function appears on the BSDs.  The daemon() function first appeared in  4.4BSD.

NOTES
       The  glibc  implementation  can  also  return  -1  when /dev/null exists but is not a character device with the
       expected major and minor numbers.  In this case errno need not be set.

SEE ALSO
       fork(2), setsid(2)

COLOPHON
       This page is part of release 3.22 of the Linux man-pages project.  A description of the project,  and  informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



GNU                               2009-05-02                         DAEMON(3)