How to get the main funciton name when calling another function inside?

Question

for eg, one RFC named A,inside A,a funtion B is called.when the processing is at B now,how can i get the main RFC name(A)?
any help will be much appricated.

Answer 1

> just see SM50,there is a column called 'Report',it shows the program id the proess is now processing.but i don't know its main program or say it 'the process's first excuting program',how can i get it programmatically?
I'm still not sure to understand. The program in SM50 is the current main program (not the first). It is stored in SY-REPID system variable. Or use this code:
DATA lt_callstack_long TYPE abap_callstack.
DATA ls_callstack_long TYPE LINE OF abap_callstack.
CALL FUNCTION 'SYSTEM_CALLSTACK'
      IMPORTING
        callstack    = lt_callstack_long.
READ TABLE lt_callstack_long INDEX 1 INTO ls_callstack_long.
WRITE : / 'current main program is:', ls_callstack_long-mainprogram.
If you want to know the frame program (the first called), use SY-CPROG, or use this code:
DATA lt_callstack_long TYPE abap_callstack.
DATA ls_callstack_long TYPE LINE OF abap_callstack.
CALL FUNCTION 'SYSTEM_CALLSTACK'
      IMPORTING
        callstack    = lt_callstack_long.
" read last line = first called program
DESCRIBE TABLE lt_callstack_long. "to make sy-tfill = number of lines
READ TABLE lt_callstack_long INDEX sy-tfill INTO ls_callstack_long.
WRITE : / 'First main program is:', ls_callstack_long-mainprogram.