Use DISPLAY_REG_SET_VALUE to perform the action on the display host's registry (the local host when the application is run with a standard runtime; the thin client when the application is run with the thin client). Use REG_SET_VALUE to perform the action on the server host's registry (the local host when the application is run with a standard runtime, and the application host when the application is run with the thin client).
CALL "REG_SET_VALUE" 
    USING OPEN-KEY-HANDLE, VALUE,
    GIVING STATUS-CODE 
               or
CALL "REG_SET_VALUE"
    USING OPEN-KEY-HANDLE, VALUE, SUBKEY-NAME,
    GIVING STATUS-CODE 
               | OPEN-KEY-HANDLE Usage unsigned-long | Handle of a currently open key or one of the following predefined handles of keys that are always open (defined in 
                              acugui.def): 
 | 
| VALUE PIC X(n) | String containing the value to set for the specified key. | 
| SUBKEY-NAME PIC X(n) (optional) | Name of a subkey of OPEN-KEY-HANDLE with which to associate a value. If there is no existing subkey matching the name specified, REG_SET_VALUE will first create it. If SUBKEY-NAME is omitted or contains an empty string, the specified value will be associated with the key identified by OPEN-KEY-HANDLE. | 
| STATUS-CODE Numeric data item. | Receives the return status of the call to Microsoft's RegSetValue function. A return status of zero indicates success; non-zero indicates that an error occurred. |