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/*
* Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 1999-2001 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: app.h,v 1.8 2007/06/19 23:47:18 tbox Exp $ */
#ifndef ISC_APP_H
#define ISC_APP_H 1
/*****
***** Module Info
*****/
/*! \file isc/app.h
* \brief ISC Application Support
*
* Dealing with program termination can be difficult, especially in a
* multithreaded program. The routines in this module help coordinate
* the shutdown process. They are used as follows by the initial (main)
* thread of the application:
*
*\li isc_app_start(); Call very early in main(), before
* any other threads have been created.
*
*\li isc_app_run(); This will post any on-run events,
* and then block until application
* shutdown is requested. A shutdown
* request is made by calling
* isc_app_shutdown(), or by sending
* SIGINT or SIGTERM to the process.
* After isc_app_run() returns, the
* application should shutdown itself.
*
*\li isc_app_finish(); Call very late in main().
*
* Applications that want to use SIGHUP/isc_app_reload() to trigger reloading
* should check the result of isc_app_run() and call the reload routine if
* the result is ISC_R_RELOAD. They should then call isc_app_run() again
* to resume waiting for reload or termination.
*
* Use of this module is not required. In particular, isc_app_start() is
* NOT an ISC library initialization routine.
*
* \li MP:
* Clients must ensure that isc_app_start(), isc_app_run(), and
* isc_app_finish() are called at most once. isc_app_shutdown()
* is safe to use by any thread (provided isc_app_start() has been
* called previously).
*
* \li Reliability:
* No anticipated impact.
*
* \li Resources:
* None.
*
* \li Security:
* No anticipated impact.
*
* \li Standards:
* None.
*/
#include <isc/eventclass.h>
#include <isc/lang.h>
#include <isc/result.h>
typedef isc_event_t isc_appevent_t;
#define ISC_APPEVENT_FIRSTEVENT (ISC_EVENTCLASS_APP + 0)
#define ISC_APPEVENT_SHUTDOWN (ISC_EVENTCLASS_APP + 1)
#define ISC_APPEVENT_LASTEVENT (ISC_EVENTCLASS_APP + 65535)
ISC_LANG_BEGINDECLS
isc_result_t
isc_app_start(void);
/*!<
* \brief Start an ISC library application.
*
* Notes:
* This call should be made before any other ISC library call, and as
* close to the beginning of the application as possible.
*/
isc_result_t
isc_app_onrun(isc_mem_t *mctx, isc_task_t *task, isc_taskaction_t action,
void *arg);
/*!<
* \brief Request delivery of an event when the application is run.
*
* Requires:
* isc_app_start() has been called.
*
* Returns:
* ISC_R_SUCCESS
* ISC_R_NOMEMORY
*/
isc_result_t
isc_app_run(void);
/*!<
* \brief Run an ISC library application.
*
* Notes:
*\li The caller (typically the initial thread of an application) will
* block until shutdown is requested. When the call returns, the
* caller should start shutting down the application.
*
* Requires:
*\li isc_app_start() has been called.
*
* Ensures:
*\li Any events requested via isc_app_onrun() will have been posted (in
* FIFO order) before isc_app_run() blocks.
*
* Returns:
*\li ISC_R_SUCCESS Shutdown has been requested.
*\li ISC_R_RELOAD Reload has been requested.
*/
isc_result_t
isc_app_shutdown(void);
/*!<
* \brief Request application shutdown.
*
* Notes:
*\li It is safe to call isc_app_shutdown() multiple times. Shutdown will
* only be triggered once.
*
* Requires:
*\li isc_app_run() has been called.
*
* Returns:
*\li ISC_R_SUCCESS
*\li ISC_R_UNEXPECTED
*/
isc_result_t
isc_app_reload(void);
/*!<
* \brief Request application reload.
*
* Requires:
*\li isc_app_run() has been called.
*
* Returns:
*\li ISC_R_SUCCESS
*\li ISC_R_UNEXPECTED
*/
void
isc_app_finish(void);
/*!<
* \brief Finish an ISC library application.
*
* Notes:
*\li This call should be made at or near the end of main().
*
* Requires:
*\li isc_app_start() has been called.
*
* Ensures:
*\li Any resources allocated by isc_app_start() have been released.
*/
void
isc_app_block(void);
/*!<
* \brief Indicate that a blocking operation will be performed.
*
* Notes:
*\li If a blocking operation is in process, a call to isc_app_shutdown()
* or an external signal will abort the program, rather than allowing
* clean shutdown. This is primarily useful for reading user input.
*
* Requires:
* \li isc_app_start() has been called.
* \li No other blocking operations are in progress.
*/
void
isc_app_unblock(void);
/*!<
* \brief Indicate that a blocking operation is complete.
*
* Notes:
* \li When a blocking operation has completed, return the program to a
* state where a call to isc_app_shutdown() or an external signal will
* shutdown normally.
*
* Requires:
* \li isc_app_start() has been called.
* \li isc_app_block() has been called by the same thread.
*/
ISC_LANG_ENDDECLS
#endif /* ISC_APP_H */
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