trusty (3) daemon.3.gz

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  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.

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 3.54 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/.