NAME
daemon - run in the background SYNOPSIS
#include
int daemon(int nochdir, int noclose); Feature Test Macro Requirements for glibc (see featuretestmacros(7)): daemon(): BSDSOURCE || (XOPENSOURCE && XOPENSOURCE < 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 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). ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌──────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────┼───────────────┼─────────┤
│daemon() │ Thread safety │ MT-Safe │ └──────────┴───────────────┴─────────┘ 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
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GNU 2009-12-05 DAEMON(3)