SAP & ABAP book (in french) :
https://books.google.fr/books?id=xMNPSTECHhoC&printsec=frontcover&hl=fr
SAP & ABAP book (in french) :
https://books.google.fr/books?id=xMNPSTECHhoC&printsec=frontcover&hl=fr
If you want to merge PDF files on SAP server, you will need  a third party software installed on SAP Server.
Here is one solution with PDF ToolKit :
Convert 2 digits ISO language (LAISO) to 1 digit SAP language key (SPRAS) and reverse:
CONVERSION_EXIT_ISOLA_INPUT Convert 2 digits ISO Lang ==> 1 digit lang. key CONVERSION_EXIT_ISOLA_OUTPUT Convert 1 digit lang. Key ==> 2 digits ISO Lang.
Transaction KO03.
✔ Change some parameteres in the form ouput parameters :
  lst_outparms-device   = 'MAIL'.   " Format for mail sending
  lst_outparms-nodialog = 'X'.      " Do not display PDF
  lst_outparms-getpdf   = 'X'.      " and get PDF source.
 
✔ Retrieve the PDF code in form ouput structure of your form function :
  /1bcdwb/formoutput = ls_formoutput
 
✔ Convert PDF code in xstring to binary :
" DATA lt_att_content_hex  TYPE solix_tab. " Table type for mail attachment.
  CALL FUNCTION 'SCMS_XSTRING_TO_BINARY'
    EXPORTING
      buffer     = ls_formoutput-pdf
*     APPEND_TO_TABLE = ' '
*   IMPORTING
*     OUTPUT_LENGTH =
    TABLES
      binary_tab = lt_att_content_hex.
 
✔ Use the table lt_att_content_hex to send the PDF by mail, check post : Send mail using BCS class
Several possibilities.
Use FM TH_IN_UPDATE_TASK:
  DATA : lv_in_updtask TYPE sy-subrc.
  CALL FUNCTION 'TH_IN_UPDATE_TASK' 
    IMPORTING in_update_task = lv_in_updtask. 
  " lv_in_updtask = 1 if running in update task, 
  " else, lv_in_updtask = 0.
Use class CL_SYSTEM_TRANSACTION_STATE:
  IF CL_SYSTEM_TRANSACTION_STATE=>GET_IN_UPDATE_TASK( ) EQ 0 .
   " Code when not running in update task... 
  ENDIF.
Search tag: update process