FairCom ISAM for C

ctSysQueueRead

Read data from the queue.

Short Name

ctSysQueueRead()

Type

ISAM function.

Declaration

NINT ctSysQueueRead(NINT qhandle, pVOID buffer, NINT buflen, LONG timeout)

Description

Data is read from the queue by calling ctSysQueueRead().

Parameter qhandle is a system queue handle returned by a call to ctSysQueueOpen(), while timeout specifies a millisecond time that ctSysQueueRead() will block waiting for data. A timeout of ctWAITFOREVER will cause ctSysQueueRead() to block until data is available in the queue. Parameter buffer is a pointer to a memory block large enough to hold the next message in the queue, and buflen indicates the size in bytes of buffer.

ctSysQueueMlen() may be used to retrieve the next message length, while ctSysQueueCount() may be used to retrieve the number of messages waiting in the queue.

Return

Value	Symbolic Constant	Explanation
0	NO_ERROR	Successful function.
90	NQUE_ERR	Could not create queue.
514	CQUE_ERR	Queue has already been closed.
638	TQUE_ERR	Queue message truncated to fit.

See FairCom DB Error Codes for a complete listing of valid FairCom DB error values.

Example

TEXT msg[128];

NINT eRet = ctSysQueueRead(qhandle, msg, sizeof(msg), ctWAITFOREVER);

if (eRet)

printf("ctSysQueueRead failed with code %d\n", eRet);

Limitations

Client/Server mode only.