daemon

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 ("/"); otherwise,

       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.

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  suc-
       cess  daemon()  returns  zero.  If an error occurs, daemon() returns -1
       and sets errno to any of the errors specified for the fork(2) and  set-
       sid(2).

CONFORMING TO
       Not in POSIX.1-2001.  A similar function appears on the BSDs.  The dae-
       mon() 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 3.23 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



GNU                               2009-05-02                         DAEMON(3)