1DAEMON(3)                  Linux Programmer's Manual                 DAEMON(3)
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NAME

6       daemon - run in the background
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SYNOPSIS

9       #include <unistd.h>
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11       int daemon(int nochdir, int noclose);
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DESCRIPTION

14       The daemon() function is for programs wishing to detach themselves from
15       the controlling terminal and run in the background as system daemons.
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17       Unless the argument nochdir is non-zero, daemon() changes  the  current
18       working directory to the root ("/").
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20       Unless  the  argument noclose is non-zero, daemon() will redirect stan‐
21       dard input, standard output and standard error to /dev/null.
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RETURN VALUE

24       (This function forks, and if  the  fork()  succeeds,  the  parent  does
25       _exit(0),  so that further errors are seen by the child only.)  On suc‐
26       cess zero will be returned.  If an error occurs,  daemon()  returns  -1
27       and  sets  the global variable errno to any of the errors specified for
28       the library functions fork(2) and setsid(2).
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SEE ALSO

31       fork(2), setsid(2)
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NOTES

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

39       Not in POSIX.1-2001.  A similar function appears on the BSDs.  The dae‐
40       mon() function first appeared in 4.4BSD.
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44BSD MANPAGE                       1993-06-09                         DAEMON(3)