Prevent multiple program submissions

You may want to prevent users to submit the same program twice for performance reasons. Here is a code snippet to prevent this, written in R/3 4.6C.

*---------------------------------------------------------------------*
*       FORM check_running                                            *
*---------------------------------------------------------------------*
*       ........                                                      *
*---------------------------------------------------------------------*
FORM check_running.
*
* For some background update jobs, you might want to stop the
* user from submitting the jobs twice.
*
* Do this checks to prevent the users from submitting the
* same background job twice.
*
* Perform the checks before starting your programs.
* do this check only if sy-batch = 'X'
*
*
*
  TYPES :

  BEGIN OF x_job_data,
          jobname  LIKE tbtco-jobname,
          jobcount LIKE tbtco-jobcount,
          strtdate LIKE tbtco-strtdate,
          strttime LIKE tbtco-strttime,
          END OF x_job_data.

  DATA: 
        curr_jobname    LIKE tbtcm-jobname,
        curr_jobcount   LIKE tbtcm-jobcount,
        g_jobcount      LIKE tbtcjob-jobcount,
        g_jobname       LIKE tbtcjob-jobname,
        t_job_table     TYPE STANDARD TABLE OF x_job_data
                        WITH HEADER LINE,
        t_joblog        TYPE STANDARD TABLE OF tbtc5
                        WITH HEADER LINE,
        t_jobstep       TYPE STANDARD TABLE OF tbtcstep
                        WITH HEADER LINE.

*
* Get own jobdata
  CALL FUNCTION 'GET_JOB_RUNTIME_INFO'
       IMPORTING
            jobcount        = curr_jobcount
            jobname         = curr_jobname
       EXCEPTIONS
            no_runtime_info = 1
            OTHERS          = 2.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
            WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.

* read all other running jobs
  SELECT * FROM tbtco
           INTO CORRESPONDING FIELDS OF TABLE t_job_table
    WHERE jobcount <> curr_jobcount
      AND strtdate = sy-datum
      AND strttime < sy-uzeit
      AND status   = 'R'.
*
  IF sy-subrc = 0.
    LOOP AT t_job_table.
      g_jobcount = t_job_table-jobcount.
      g_jobname  = t_job_table-jobname.
*     Read all jobsteps belonging to job
      CALL FUNCTION 'BP_JOB_READ'
        EXPORTING
          job_read_jobcount           = g_jobcount
          job_read_jobname            = g_jobname
          job_read_opcode             = '20'
*         JOB_STEP_NUMBER             =
*       importing
*         job_read_jobhead            =
        TABLES
          job_read_steplist           = t_jobstep
*       changing
*         ret                         =
        EXCEPTIONS
          invalid_opcode              = 1
          job_doesnt_exist            = 2
          job_doesnt_have_steps       = 3
          OTHERS                      = 4
                .
      IF sy-subrc = 0.
*       check if current program is part of the job
        LOOP AT t_jobstep.
          IF t_jobstep-program = sy-cprog.
*           program found, issue an error-message          
            MESSAGE i100 WITH 'Please wait '
                              'Program is already part of job'.

            MESSAGE a999 WITH g_jobname
                    'which is started on '
                     t_job_table-strtdate t_job_table-strttime.

          ENDIF.
        ENDLOOP.
      ENDIF.
    ENDLOOP.
  ENDIF.
ENDFORM.