text: /*-
   * Public Domain 2014-2016 MongoDB, Inc.
   * Public Domain 2008-2014 WiredTiger, Inc.
   *
   * This is free and unencumbered software released into the public domain.
   *
   * Anyone is free to copy, modify, publish, use, compile, sell, or
   * distribute this software, either in source code form or as a compiled
   * binary, for any purpose, commercial or non-commercial, and by any
   * means.
   *
   * In jurisdictions that recognize copyright laws, the author or authors
   * of this software dedicate any and all copyright interest in the
   * software to the public domain. We make this dedication for the benefit
   * of the public at large and to the detriment of our heirs and
   * successors. We intend this dedication to be an overt act of
   * relinquishment in perpetuity of all present and future rights to this
   * software under copyright law.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
   * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   *
   * ex_event_handler.c
   *	Demonstrate how to use the WiredTiger event handler mechanism.
   *
   */
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include <wiredtiger.h>
  
  static const char *home;
  
  int handle_wiredtiger_error(
      WT_EVENT_HANDLER *, WT_SESSION *, int, const char *);
  int handle_wiredtiger_message(WT_EVENT_HANDLER *, WT_SESSION *, const char *);
  
  /*! [Function event_handler] */
  /*
   * Create our own event handler structure to allow us to pass context through
   * to event handler callbacks. For this to work the WiredTiger event handler
   * must appear first in our custom event handler structure.
   */
  typedef struct {
  	WT_EVENT_HANDLER h;
  	const char *app_id;
  } CUSTOM_EVENT_HANDLER;
  
  /*
   * handle_wiredtiger_error --
   *	Function to handle error callbacks from WiredTiger.
   */
  int
  handle_wiredtiger_error(WT_EVENT_HANDLER *handler,
      WT_SESSION *session, int error, const char *message)
  {
  	CUSTOM_EVENT_HANDLER *custom_handler;
  
  	/* Cast the handler back to our custom handler. */
  	custom_handler = (CUSTOM_EVENT_HANDLER *)handler;
  
  	/* Report the error on the console. */
  	fprintf(stderr,
  	    "app_id %s, thread context %p, error %d, message %s\n",
  	    custom_handler->app_id, session, error, message);
  
  	return (0);
  }
  
  /*
   * handle_wiredtiger_message --
   *	Function to handle message callbacks from WiredTiger.
   */
  int
  handle_wiredtiger_message(
      WT_EVENT_HANDLER *handler, WT_SESSION *session, const char *message)
  {
  	/* Cast the handler back to our custom handler. */
  	printf("app id %s, thread context %p, message %s\n",
  	    ((CUSTOM_EVENT_HANDLER *)handler)->app_id, session, message);
  
  	return (0);
  }
  /*! [Function event_handler] */
  
  static int
  config_event_handler(void)
  {
  	WT_CONNECTION *conn;
  	WT_SESSION *session;
  	int ret;
  
  	/*! [Configure event_handler] */
  	CUSTOM_EVENT_HANDLER event_handler;
  
  	event_handler.h.handle_error = handle_wiredtiger_error;
  	event_handler.h.handle_message = handle_wiredtiger_message;
  	/* Set handlers to NULL to use the default handler. */
  	event_handler.h.handle_progress = NULL;
  	event_handler.h.handle_close = NULL;
  	event_handler.app_id = "example_event_handler";
  
  	ret = wiredtiger_open(home,
  	    (WT_EVENT_HANDLER *)&event_handler, "create", &conn);
  	/*! [Configure event_handler] */
  
  	/* Make an invalid API call, to ensure the event handler works. */
  	(void)conn->open_session(conn, NULL, "isolation=invalid", &session);
  
  	if (ret == 0)
  		ret = conn->close(conn, NULL);
  
  	return (ret);
  }
  
  int
  main(void)
  {
  	/*
  	 * Create a clean test directory for this run of the test program if the
  	 * environment variable isn't already set (as is done by make check).
  	 */
  	if (getenv("WIREDTIGER_HOME") == NULL) {
  		home = "WT_HOME";
  		(void)system("rm -rf WT_HOME && mkdir WT_HOME");
  	} else
  		home = NULL;
  
  	return (config_event_handler());
  }
  