#ifndef foodaemonforkhfoo
#define foodaemonforkhfoo

/* $Id$ */

/*
 * This file is part of libdaemon.
 *
 * libdaemon is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * libdaemon is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with libdaemon; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 */

#include <sys/types.h>

#ifdef __cplusplus
extern "C" {
#endif

/** \mainpage libdaemon
 *
 * libdaemon
 * 
 * For a brief explanation of libdaemons's purpose, have a look on the
 * README file. Thank you!
 *
 */

/** \example testd.c
 * This is an example for the usage of libdaemon
 */

/** \file
 *
 * Contains an API for doing a daemonizing fork(). 
 *
 * You may daemonize by calling daemon_fork(), a function similar to
 * the plain fork(). If you want to return a return value of the
 * initialization procedure of the child from the parent, you may use
 * the daemon_retval_xxx() functions.
 */

/** Does a daemonizing fork(). For the new daemon process STDIN,
 * STDOUT, STDERR are connected to /dev/null, the process is a session
 * leader, the current directory is changed to /, the umask is set to
 * 777.
 * @return On success, the PID of the child process is returned in the
 * parent's thread of execution, and a 0 is returned in the child's
 * thread of execution. On failure, -1 will be returned in the
 * parent's context, no child process will be created, and errno will
 * be set appropriately.
 */
pid_t daemon_fork(void);

/** Allocate and initialize resources required by the
 * daemon_retval_xxx() functions. These functions allow the child to
 * send a value to the parent after completing its initialisation.
 * Call this in the parent before forking.
 * @return zero on success, nonzero on failure.
 */
int daemon_retval_init(void);

/** Frees the resources allocated by daemon_retval_init(). This should
 * be called if neither daemon_retval_wait() nor daemon_retval_send()
 * is called in the current process. The resources allocated by
 * daemon_retval_init() should be freed in both parent and daemon
 * process. This may be achieved by using daemon_retval_wait()
 * resp. daemon_retval_send(), or by using daemon_retval_done().
 */
void daemon_retval_done(void);

/** Return the value sent by the child via the daemon_retval_send()
 * function, but wait only the specified number of seconds before
 * timing out and returning a negative number. Should be called just
 * once from the parent process only. A subsequent call to
 * daemon_retval_done() in the parent is ignored.
 *
 * @param timeout Thetimeout in seconds
 * @return The integer passed daemon_retval_send() in the daemon process, or -1 on failure.
 */
int daemon_retval_wait(int timeout);

/** Send the specified integer to the parent process. Do not send -1
 * because this signifies a library error. Should be called just once
 * from the daemon process only. A subsequent call to
 * daemon_retval_done() in the daemon is ignored.  @param s The
 * integer to pass to daemon_retval_wait() in the parent process
 * @return Zero on success, nonzero on failure.
 */
int daemon_retval_send(int s);

#ifdef __cplusplus
}
#endif

#endif