监测事件功能由“启动监测”(STRWCH) 命令或“启动监测”(QSCSWCH) API 启动以通过在发生指定事件时调用出口程序来通知用户。事件可以是发送至消息队列的消息、作业记录、许可内码记录项或产品活动记录 (PAL) 项，它显示磁盘单元和磁带单元（通信期间）中或工作站上发生的错误。
用户编写的出口程序是在监测选项设置参数中指定的环境下调用的。以下是监测事件出口程序的示例，它是用 C 语言编写的。
从此出口程序着手来帮助您创建您自己的监测事件出口程序。可修改代码以允许程序执行其他功能。
/*************************************************************************
** file = mywchpgm.c
**
** Example of an Exit Program for Watch for Event.
**
** This program will be called by the watch for event support when CPF0907
** message is sent to the history log (QHST message queue in library QSYS).
**
** The program will call a cleanup program to free system storage and,
** if the available storage is less than 5%, the program will perform some
** more actions (not defined).
**
**************************************************************************/
#include <decimal.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <except.h> /* _INTRPT_Hndlr_Parms_T is typedefed */
#include <escwcht.h> /* Include for Watch Exit Program packaged in */
/* QSYSINC/H Source Physical File */
/****************** Prototypes *******************************************/
void UNEXPECTED_HDLER (_INTRPT_Hndlr_Parms_T *errmsg);
/* Declare variables to receive parameters */
char watch_option_setting[10],
session_ID[10],
* error_detected_ptr;
typedef struct {
Qsc_Watch_For_Msg_t msg_data;
char VarData[8776]; /* variable length data */
} MsgFullData_t;
MsgFullData_t * MsgFullData;
int main (int argc, char *argv[])
{
char * cAvailStorage[4];
decimal(7,4) dAvailStorage;
/* Variables to call a command */
int rc;
char cmdtorun[128];
#define CALL_MYCLNUP "CALL PGM(MYLIB/MYCLNUP)"
/*********************************************************************/
/* Turn exception monitor on. */
/*********************************************************************/
#pragma exception_handler (UNEXPECTED_HDLER, 0, 0, _C2_MH_ESCAPE)
memcpy(watch_option_setting,argv[1],10);
memcpy(session_ID,argv[2],10);
error_detected_ptr = argv[3];
MsgFullData = (MsgFullData_t *) argv[4];
/* Verify if the exit program was called because a watched message */
/* occurred. This verification is useful if you have a watch */
/* session waiting for a message event and for a Licensed Internal Code log event */
if (memcmp(watch_option_setting,"*MSGID ",10)==0) {
/* Verify if the message ID that occurred is CPF0907 */
/* This verification is useful if you are watching for more than */
/* one message in the same watch session */
if (memcmp(MsgFullData->msg_data.Message_ID,"CPF0907",7)==0) {
/* Call cleanup program to free space */
strcpy(cmdtorun,CALL_MYCLNUP);
rc = system(cmdtorun);
if (rc == 0) {
/* Determine if the available storage space is less than 5% */
/* to do some extra processing */
if (MsgFullData->msg_data.Length_Of_Replacement_Data > 0) {
/* The remaining storage comes in the 4th field data in the */
/* message replacement variable. See CPF0907 message */
/* description for a better understanding */
memcpy(cAvailStorage,
(char *) (argv[4] +
MsgFullData->msg_data.Offset_Replacement_Data + 66),
4);
dAvailStorage = *(decimal(7,4) *) cAvailStorage;
if (dAvailStorage <= 5.00) {
/* Do some extra processing */
}
}
}
else { /* Error on clean-up program */
UNEXPECTED_HDLER(NULL); /* Return error and exit */
}
}
else {
/* Add code in case you are expecting any other message ID */
}
}
/* Verify if the exit program was called because a Licensed Internal Code log occurred */
else if (memcmp(watch_option_setting,"*LICLOG ",10)==0) {
/* Not needed for this watch session */
}
memcpy(error_detected_ptr," ",10); /* No error detected by
watch exit program, return blanks and
continue watching */
#pragma disable_handler
return (0);
}
/********************************************************************/
/* FUNCTION NAME: UNEXPECTED_HDLER */
/* */
/* FUNCTION : Handle unexpected exceptions that may occur */
/* during the invocation of this pgm. */
/* */
/********************************************************************/
void UNEXPECTED_HDLER (_INTRPT_Hndlr_Parms_T *errmsg)
{
memcpy(error_detected_ptr,"*ERROR ",10); /* An error occurred
on the watch exit program. Return *ERROR
and End the watch session */
exit(EXIT_FAILURE);
}