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 back-
       ground as system daemons.

       If nochdir is zero, daemon() changes the calling process's current working directory to the root directory ("/");  other-
       wise, 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.

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 3.25 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                                                        2009-12-05                                                  DAEMON(3)