Advanced Queuing - Oracle

LNOCIError *errhp;
LNOCISvcCtx *svchp;
LNOCIAQDeqOptions *deqopt;
message *mesg = (message *)0;
null_message *mesgind = (null_message *)0;
static void deqmesg(buf, buflen)
text *buf;
ub4 *buflen;
{
AQ and Memory Usage
OCIType *mesgtdo = (OCIType *)0; /* type descr of SCOTT.MESSAGE */
ub4 wait = 60; /* timeout after 60 seconds */
ub4 navigation = OCI_DEQ_FIRST_MSG;/* always get head of q */
/* Get the type descriptor object for the type SCOTT.MESSAGE: */
checkerr(errhp, OCITypeByName(envhp, errhp, svchp,
(CONST text *)"SCOTT", strlen("SCOTT"),
(CONST text *)"MESSAGE", strlen("MESSAGE"),
(text *)0, 0, OCI_DURATION_SESSION,
OCI_TYPEGET_ALL, &mesgtdo));
/* Set wait time, navigation in dequeue options: */
checkerr(errhp, OCIAttrSet(deqopt, OCI_DTYPE_AQDEQ_OPTIONS,
(dvoid *)&wait, 0, OCI_ATTR_WAIT, errhp));
checkerr(errhp, OCIAttrSet(deqopt, OCI_DTYPE_AQDEQ_OPTIONS,
(dvoid *)&navigation, 0,
OCI_ATTR_NAVIGATION, errhp));
/*
* Dequeue the message and commit. The memory for the payload will be
* automatically allocated/resized by OCI:
*/
checkerr(errhp, OCIAQDeq(svchp, errhp, (CONST text *)"msgqueue",
deqopt, 0, mesgtdo, (dvoid **)&mesg,
(dvoid **)&mesgind, 0, 0));
checkerr(errhp, OCITransCommit(svchp, errhp, (ub4) 0));
/* Copy the message payload text into the user buffer: */
if (mesgind->null_data)
*buflen = 0;
else
memcpy((dvoid *)buf, (dvoid *)OCIStringPtr(envhp, mesg->data),
(size_t)(*buflen = OCIStringSize(envhp, mesg->data)));
Oracle Advanced Queuing by Example A-85