MQOO_FAIL_IF_QUIESCING + MQOO_BROWSE + MQOO_INPUT_EXCLUSIVE

  MsgDesc := MQMD_DEFAULT;
  GetMsgOptions := MQGMO_DEFAULT;
  GetMsgOptions.Options := MQGMO_BROWSE_FIRST;

MQOO_FAIL_IF_QUIESCING + MQOO_INPUT_EXCLUSIVE

  MsgDesc := MQMD_DEFAULT;
  MsgDesc.Version := MQMD_CURRENT_VERSION;
  MsgDesc.MsgFlags := MQMF_SEGMENTATION_ALLOWED;

  GetMsgOptions := MQGMO_DEFAULT;
  GetMsgOptions.Options := MQGMO_BROWSE_FIRST;
  GetMsgOptions.Options := MQGMO_COMPLETE_MSG;

  MsgDesc := MQMD_DEFAULT;
  MsgDesc.Version := MQMD_CURRENT_VERSION;
  MsgDesc.MsgFlags := MQMF_SEGMENTATION_ALLOWED;

  GetMsgOptions := MQGMO_DEFAULT;
  GetMsgOptions.Options := MQGMO_SYNCPOINT;
//  GetMsgOptions.Options := MQGMO_COMPLETE_MSG;

This is the only option that causes the queue manager to reassemble message segments. 
If not specified, segments are returned individually to the application if they are present on the queue 
(and they satisfy the other selection criteria specified on the MQGET call). 
Applications that do not want to receive individual segments must always specify MQGMO_COMPLETE_MSG.
...
MQGMO_COMPLETE_MSG can be specified with any of the other MQGMO_* options apart from 
MQGMO_SYNCPOINT_IF_PERSISTENT, and with any of the MQMO_* options apart from MQMO_MATCH_OFFSET.

When an application puts or gets messages in groups or segments of logical messages, the queue manager 
retains information relating to the message group and logical message for the last successful MQPUT and MQGET calls. 
This information is associated with the queue handle, and includes such things as: 
The values of the GroupId, MsgSeqNumber, Offset, and MsgFlags fields in MQMD.
Whether the message is part of a unit of work.
For the MQPUT call: whether the message is persistent or nonpersistent.
 The queue manager keeps three sets of group and segment information, one set for each of the following: 
The last successful MQPUT call (this can be part of a unit of work).
The last successful MQGET call that removed a message from the queue (this can be part of a unit of work).
The last successful MQGET call that browsed a message on the queue (this cannot be part of a unit of work).