The Change  Object  Description 4  command provides  a general  purpose
solution when  a program wants  to prompt for  a CHGxxx command.   Only
typical  object types and attributes are  supported.  Assuming you have
provided a  proper interface  to  CHGOBJD4, the  command will  complete
normally  whether the  change has  been  made, the  command prompt  was
cancelled,  or  the command  failed.   The  ESCMSGID parameter  will be
blank if a successful change was made.

Assume your program is reading  objects from a DSPOBJD outfile and  you
want to  allow the  user to  change the  object.   A typical  series of
commands would be:

             DCLF       FILE(QADSPOBJ)
             DCL        &ESCMSGID *CHAR LEN(7)
             DCL        &MSGTXT *CHAR LEN(75)
             DCL        &DIAGMSGID *CHAR LEN(7)
             DCL        &DIAGMSGTXT *CHAR LEN(75)
              .
             CHGOBJD4   OBJ(&ODLBNM/&ODOBNM) OBJTYPE(&ODOBTP) +
                          MSGTXT(&MSGTXT) ESCMSGID(&ESCMSGID) +
                          DIAGMSGID(&DIAGMSGID) DIAGMSGTXT(&DIAGMSGTXT)
             IF         (&ESCMSGID *EQ ' ') DO /* Successful *.
                        /*                                        */
                        /*   Your handling of a successful change */
                        /*                                        */
             ENDDO      /* Successful */
             IF         (&ESCMSGID *NE ' ') DO /* Failed */
                        /*                                        */
                        /*   Your handling of a failure           */
                        /*                                        */
             ENDDO      /* Failed */

If the  CHGxxx command completes successfully  and returns a completion
message, the MSGTXT  variable will contain  the first 75  bytes of  the
completion message type.  The ESCMSGID parameter will be blank.

If an  error occurs  when the  command is run,  the ESCMSGID  parameter
will  contain  the  system escape  ID  and  the  MSGTXT parameter  will
contain  the  first 75  bytes of  the message  text.   If  a diagnostic
message also exists,  the DIAGMSGID and  DIAGMSGTXT return values  will
also be filled  with the information for the  first diagnostic message.

If  the user  cancels the  command prompt, CPF6801  ('Command prompting
ended ...')  will  be  returned  for the  ESCMSGID  parameter  and  the
CPF6801 error text will be in the MSGTXT return value.

If the  object type (or  attribute) is not  supported, TAA9891  will be
returned  for  the  ESCMSGID parameter  with  appropriate  text in  the
MSGTXT parameter.

Using RTVOBJD
-------------

If you are using  RTVOBJD instead of reading  the DSPOBJD outfile,  you
may also follow it with the CHGOBJD4 command.

CHGOBJD4 escape messages you can monitor for
--------------------------------------------

None.

CHGOBJD4 Command parameters                           *CMD
---------------------------

   OBJ           The qualified name of  the object to be changed.   The
                 library value  defaults to *LIBL.   A specific library
                 or *CURLIB may also be used.

   OBJTYPE       The  object type to  be changed.   Only typical object
                 types and attributes are supported.

   ESCMSGID      The escape  message ID  if the  CHGxxx command  failed
                 or   was  cancelled.     If   the  command   completes
                 successfully,  ESCMSGID  will  be blank.    This  is a
                 required return  variable that  must be  specified  as
                 *CHAR LEN(7).

   MSGTXT        The first  75 bytes  of either the  completion message
                 (if  any) or the escape  message.  This  is a required
                 return  variable  that  must  be  specified  as  *CHAR
                 LEN(75).

   DIAGMSGID     The  diagnostic  message  ID  if  the  CHGxxx  command
                 failed  and a  diagnostic message  type exists.   Only
                 the  message  ID of  the  first diagnostic  message is
                 returned.   If  the  command  completes  successfully,
                 the value  will be blank.   This is a  required return
                 variable that must be specified as *CHAR LEN(7).

   DIAGMSGTXT    The  first 75  bytes of  the first  diagnostic message
                 associated  with   the   escape  message.      If   no
                 diagnostic  message   occurred,  the  value   will  be
                 blank.   This is a required  return variable that must
                 be specified as *CHAR LEN(75).

Restrictions
------------

None.

Prerequisites
-------------

The following TAA Tools must be on your system:

     CHGDTAQD        Change data queue description
     CHKOBJ3         Check object 3
     RTVDTAQD        Retrieve data queue description
     SNDESCINF       Send escape information
     SNDESCMSG       Send escape message

Implementation
--------------

None, the tool is ready to use.

Objects used by the tool
------------------------

   Object        Type    Attribute      Src member    Src file
   ------        ----    ---------      ----------    ----------

   CHGOBJD4      *CMD                   TAAOBMV       QATTCMD
   TAAOBMVC      *PGM       CLP         TAAOBMVC      QATTCL