EHLLAPI scans the query reply buffers for the destination/origin
ID (DOID) self-defining parameter (SDP) to determine the contents
of the DOID field of the query reply. If this value is X'0000',
the emulator will assign a DOID to the application and EHLLAPI will
fill in the DOID field of the query reply with the assigned ID. If
the value specified by the application in the DOID field of the query
reply is a nonzero value, the emulator will assign the specified value
as the application’s DOID, assuming that the ID has not been previously
assigned. If the specified DOID is already in use, a return code of
2 will be returned by EHLLAPI.
The application should build the Query Reply Data structures in
the application’s private memory. Refer to Query Reply Data Structures Supported by EHLLAPI, for
the detailed formats and usages of the query reply data structures
supported by EHLLAPI.
Only cursory checking is performed on the Query Reply Data. Only
the ID and the length of the structure are checked for validity.
Only one DDM base type connect is allowed per host session. If
the DDM connection supports the self-defining parameter (SDP) for
the destination origin ID (DOID), then multiple connects are allowed.
If return code RC=32 or RC=39 is received, an application is already
connected to the selected session and use of that presentation space
should be approached with caution. Conflicts with file transfer, and
other EHLLAPI applications might result.