int daemon(int nochdir, int noclose);

       #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; 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).