This routine waits until a character is input from the keyboard, then reads the input character without displaying it.
Specification
01 r-character PIC X. 01 status-code PIC S9(4) COMP-5.
CALL "CBL_READ_KBD_CHAR"
    USING r-character
    RETURNING status-code.Interface
Specifies the area used to store the input character.
Return code
The return code is set in the status-code specified in the RETURNING clause.
0: Successful
Other than 0: Failure