Copyright (c) 1999 The NetBSD Foundation, Inc.
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This code is derived from software contributed to The NetBSD Foundation
by Jason R. Thorpe.
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.Dd June 5, 1999 .Dt PIDFILE 3 .Os .Sh NAME .Nm pidfile .Nd write a daemon pid file .Sh LIBRARY .Lb libutil .Sh SYNOPSIS .Fd #include \*[Lt]util.h\*[Gt] .Ft int .Fn pidfile "const char *basename" .Sh DESCRIPTION .Fn pidfile writes a file containing the process ID of the program to the
a /var/run directory. The file name has the form
a /var/run/basename.pid . If the .Ar basename argument is NULL, .Nm will determine the program name and use that instead.
p The pid file can be used as a quick reference if the process needs to be sent a signal. When the program exits, the pid file will be removed automatically, unless the program receives a fatal signal.
p Note that only the first invocation of .Nm causes a pid file to be written; subsequent invocations have no effect unless a new .Ar basename is supplied. If called with a new .Ar basename , .Fn pidfile will remove the old pid file and writes the new one. .Sh RETURN VALUES .Fn pidfile returns 0 on success and -1 on failure. .Sh SEE ALSO .Xr atexit 3 .Sh HISTORY The .Nm function call appeared in .Nx 1.5 . .Sh BUGS
p .Fn pidfile uses .Xr atexit 3 to ensure the pidfile is unlinked at program exit. However, programs that use the .Xr _exit 2 function (for example, in signal handlers) will not trigger this behaviour.
Indexes created Fri Oct 17 09:09:57 GMT 2025