I have one input field of type C.
PARAMETERS lv_sep TYPE c.
Field lv_sep should accept only special characters.
Can you help me how i can give this constraint?
you can do checks during AT-SELECTION-SCREEN. You could for instance check the parameter lv_sep for the characters you want to accept.
AT-SELECTION-SCREEN.
if not lv_sep CO '!"§$%&/()=?'.
message text-e01 type E.
endif.