INTERNAL TABLES
SY-TABIX Current line of an internal table. It is set  only for index tables. The field is either not set or is set to 0 for hashed tables. It iset by ABAP commands APPEND,COLLECT,LOOP AT,READ TABLE,SAERCH itab FOR.
SY-TFILL After the statements DESCRIBE TABLE, LOOP AT, and READ TABLE, SY-TFILL contains the number of lines in the relevant internal table.
DATABASES ACCESS
SY-DBCNT It contains  the number of table entries processed. In an  loop it  is not set until after the ENDSELECT or ENDEXEC statement.  It is set by ABAP commands DELETE,FETCH,INSERT,MODIFY and UPDATE.
SY-SUBRC Return code set by the last ABAP statement. if it is 0 it means the statement was a success.
SYSTEM FIELDS for Screens
SY-CUCOL Horizontal cursor position. Counter begins at column 2.
SY-CUROW Vertical cursor position. Counter begins at line 1.
SY-DATAR This field contains ‘X’ if at least one input field on the screen was changed by the user , otherwise it is  space.It can be used to determine if user has made any changes and a popup can be called with a prompt e.g. POPUP_TO_CONFIRM_CHANGE.
SY-LOOPC Number of lines currently displayed in a table control. Can be used to determine the step loop blocks in the screen and for scrolling functionality.
SY-PFKEY GUI status of the current screen. This can be set in the PBO event using the SET PF-STATUS status OF PROGRAM rep statement.
SY-SCOLS Number of columns on the current screen.
SY-SROWS Number of rows on the current screen.
SY-STEPL Index of the current line in a table control. This is set in each loop pass. SY-STEPL does not have a meaningful value outside the loop (for example, during the POV event for a table line).
SY-TITLE It contains the text that appears in the title bar of the screen. For selection screens and lists it is the program name,it can  be set using the SET TITLEBAR statement.
SY-UCOMM It contains the function code that triggered the PAI event.ENTER triggers the PAI but this field will remain blank if no function code is attached to ENTER key.

Selection Screens
SY-SLSET Variant used to fill the selection screen.
SYSTEM FIELDS for Creating Lists
SY-COLNO It contains the current column during list creation starting at 1. The field is set by the output statements  WRITE,ULINE,SKIP,POSITION,NEW-LINE,NEW-PAGE and BACK (sets it to 1).
SY-LINCT It contains length of  the page in the list. Its value is  0 if the length of page is infinite.
SY-LINNO It contains the current line during list creation begining from 1, and includes the page header. SY-LINNO is set by the ABAP output statements which are same as SY-COLNO.
SY-LINSZ It contains the line width in the list. The default value is the default window width. You can change the line width of the list using the LINE-SIZE addition in the REPORT or NEW-PAGE statement. The default value is 84.
SY-PAGNO Current page during list creation.
SY-TVAR0 … SY-TVAR9 You can assign values to these variables in your programs. Their contents replace the placeholders in the list and column headers of the program in the TOP-OF-PAGE event.
SYSTEM FIELDS For Messages

 With call of MESSAGE statement following system fields are set.
SY-MSGID contains the message class.
SY-MSGNO contains the message number
SY-MSGTY contains the message type
SY-MSGV1 SY-MSGV4 These fields hold the place holders in the message.
SY-TFILLContains the number of lines in the relevant internal table.


Serkan AKKAVAK
Computer Engineer
serkurumsal@yandex.com