This routine checks whether a character was input from the keyboard.
Specification
01 key-status PIC 9(9) BINARY. 01 status-code PIC S9(4) COMP-5.
CALL "CBL_GET_KBD_STATUS"
    USING key-status
    RETURNING status-code.Interface
Specifies the area used to store key status information as follows:
0: No character was input.
1: A character was input.
Return code
The return code is set in the status-code specified in the RETURNING clause.
0: Successful
Other than 0: Failure