Log display

https://answers.sap.com/questions/1515224/how-we-can-see-application-log.html

sap sample program:SBAL_DEMO_04


CALL FUNCTION 'BAL_DSP_PROFILE_POPUP_GET'
      IMPORTING
        E_S_DISPLAY_PROFILE = V_PROFILE
      EXCEPTIONS
        OTHERS              = 1.

 V_PROFILE-USE_GRID   = 'X'.     "Use grid control for output
 V_PROFILE-POP_ADJST  = 'X'.     "Adjust popup height
 V_PROFILE-CWIDTH_OPT = 'X'.     "Optimize message list column width
 V_PROFILE-TITLE      = TEXT-M01.
 V_PROFILE-END_COL    = 110. 

 LOOP AT V_PROFILE-MESS_FCAT ASSIGNING <LV_MESS_FCAT>
                                   WHERE REF_FIELD = 'MSGTY'
                                      OR REF_FIELD = 'MSGID'
                                      OR REF_FIELD = 'MSGNO'.

    LV_CNT = LV_CNT + 1.
    CLEAR:<LV_MESS_FCAT>-NO_OUT.
    <LV_MESS_FCAT>-COL_POS = LV_CNT.

  ENDLOOP.

* Application Log: Log: Create with Header Data
  CALL FUNCTION 'BAL_LOG_CREATE'
    EXPORTING
      I_S_LOG                 = V_LOG
    IMPORTING
      E_LOG_HANDLE            = V_LOG_HANDLE
    EXCEPTIONS
      LOG_HEADER_INCONSISTENT = 1
      OTHERS                  = 2.
 APPEND V_LOG_HANDLE TO I_LOG_HANDLE.


  LOOP AT I_ERRPARAM INTO WA_ERRPARAM.

    CALL FUNCTION 'BAL_LOG_MSG_ADD'
      EXPORTING
        I_LOG_HANDLE     = V_LOG_HANDLE
        I_S_MSG          = WA_ERRPARAM
      IMPORTING
        E_S_MSG_HANDLE   = V_MSG_HANDLE
      EXCEPTIONS
        LOG_NOT_FOUND    = 1
        MSG_INCONSISTENT = 2
        LOG_IS_FULL      = 3
        OTHERS           = 4.

    IF SY-SUBRC <> 0.
*     Create Application Log
      PERFORM SYSTEM_ERROR USING 'BAL_LOG_MSG_ADD'
                                  SY-SUBRC.

    ENDIF.
  ENDLOOP.

 CALL FUNCTION 'BAL_DSP_LOG_DISPLAY'
    EXPORTING
      I_T_LOG_HANDLE       = I_LOG_HANDLE
      I_S_DISPLAY_PROFILE  = V_PROFILE
      I_AMODAL             = V_IM_NEW_SESSION
    IMPORTING
      E_S_EXIT_COMMAND     = ST_EX_EXIT_COMMAND
    EXCEPTIONS
      PROFILE_INCONSISTENT = 1
      INTERNAL_ERROR       = 2
      NO_DATA_AVAILABLE    = 3
      NO_AUTHORITY         = 4.