The CBL_GET_SCR_SIZE routine is one of a set of library routines that facilitate reading and writing attributes on the screen. This routine returns the screen size.
CALL "CBL_GET_SCR_SIZE" 
    USING DEPTH, WIDTH 
    RETURNING STATUS-CODE
               	 | DEPTH PIC X COMP-X. | On exit, contains the number of lines in the screen | 
| WIDTH PIC X COMP-X. | On exit, contains the number of columns in the screen | 
| STATUS-CODE Any numeric type | Returns 1 if successful, or 0 if not successful | 
This library routine uses the DEPTH and WIDTH parameters to return information about the size of the screen.