pidfile(3) [netbsd man page]

PIDFILE(3)						   BSD Library Functions Manual 						PIDFILE(3)

NAME

     pidfile -- write a daemon pid file

LIBRARY

     System Utilities Library (libutil, -lutil)

SYNOPSIS

     #include <util.h>

     int
     pidfile(const char *path);

DESCRIPTION

     pidfile() creates a file containing the process ID of the caller program.	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 is removed automatically, unless the program receives a fatal signal.

     If path is NULL or a plain basename (a name containing no directory components), the pid file is created in the /var/run directory.  The file
     name has the form /var/run/basename.pid.  The basename part is either the value of path if it was not NULL, or the program name as returned
     by getprogname(3) otherwise.

     If path is an absolute or relative path (i.e. it contains the '/' character), the pid file is created in the provided location.

     Note that only the first invocation of pidfile() causes a pid file to be written; subsequent invocations have no effect unless a new path is
     supplied.	If called with a new path, pidfile() will remove the old pid file and write the new one.

RETURN VALUES

     pidfile() returns 0 on success and -1 on failure.

SEE ALSO

     atexit(3)

HISTORY

     The pidfile() function call appeared in NetBSD 1.5.  Support for creating pid files in any arbitrary path was added in NetBSD 6.0.

BUGS

     pidfile() uses atexit(3) to ensure the pid file is unlinked at program exit.  However, programs that use the _exit(2) function (for example,
     in signal handlers) will not trigger this behaviour.

BSD
								  March 23, 2011							       BSD

File::Pid(3pm)						User Contributed Perl Documentation					    File::Pid(3pm)

NAME

       File::Pid - Pid File Manipulation

SYNOPSIS

	 use File::Pid;

	 my $pidfile = File::Pid->new({
	   file => '/some/file.pid',
	 });

	 $pidfile->write;

	 if ( my $num = $pidfile->running ) {
	     die "Already running: $num
";
	 }

	 $pidfile->remove;

DESCRIPTION

       This software manages a pid file for you. It will create a pid file, query the process within to discover if it's still running, and remove
       the pid file.

       new

	 my $pidfile = File::Pid->new;

	 my $thisfile = File::Pid->new({
	   file => '/var/run/daemon.pid',
	 });

	 my $thisfileandpid = File::Pid->new({
	   file => '/var/run/daemon.pid',
	   pid	=> '145',
	 });

       This constructor takes two optional paramters.

       "file" - The name of the pid file to work on. If not specified, a pid file located in "File::Spec->tmpdir()" will be created that matches
       "(File::Basename::basename($0))[0] . '.pid'". So, for example, if $0 is ~/bin/sig.pl, the pid file will be /tmp/sig.pl.pid.

       "pid" - The pid to write to a new pidfile. If not specified, $$ is used when the pid file doesn't exist. When the pid file does exist, the
       pid inside it is used.

       file

	 my $pidfile = $pidfile->file;

       Accessor/mutator for the filename used as the pid file.

       pid

	 my $pid = $pidfile->pid;

       Accessor/mutator for the pid being saved to the pid file.

       write

	 my $pid = $pidfile->write;

       Writes the pid file to disk, inserting the pid inside the file.	On success, the pid written is returned. On failure, "undef" is returned.

       running

	 my $pid = $pidfile->running;
	 die "Service already running: $pid
" if $pid;

       Checks to see if the pricess identified in the pid file is still running. If the process is still running, the pid is returned. Otherwise
       "undef" is returned.

       remove

	 $pidfile->remove or warn "Couldn't unlink pid file
";

       Removes the pid file from disk. Returns true on success, false on failure.

       program_name

       This is a utility method that allows you to determine what "File::Pid" thinks the program name is. Internally this is used when no pid file
       is specified.

SEE ALSO

       perl.

AUTHOR

       Casey West, <casey@geeknest.com>.

COPYRIGHT

	 Copyright (c) 2005 Casey West.  All rights reserved.
	 This module is free software; you can redistribute it and/or modify it
	 under the same terms as Perl itself.

perl v5.8.8							    2008-04-05							    File::Pid(3pm)