Scenario: Exit program for Watch for Event

The user-written exit program is called in the circumstances specified in the Watch option setting parameter. Here is an example of a Watch for Event exit program, which is written in C.

Use this exit program as a starting point to help you create your own watch for event exit program. You can modify the code to allow the program to perform additional functions.

/*************************************************************************
** 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);
}