C invocation

MQXWAIT (Hconn, &WaitDesc, &CompCode, &Reason);

Declare the parameters as follows:

MQHCONN  Hconn;     /* Connection handle */
MQXWD    WaitDesc;  /* Wait descriptor */
MQLONG   CompCode;  /* Completion code */
MQLONG   Reason;    /* Reason code qualifying CompCode */