MQOPEN()

Purpose

Open a pointer to a message queue

Syntax

MQOPEN(<expC> [,<expN>])

See Also

MQCLOSE(), MQCURMSGS(), MQCREATE(), MQRECEIVE(), MQSEND()

Description

The MQOPEN() function opens an existing message queue. It returns a numeric pointer when the queue is opened successfully, or a -1 if unsuccessful. The <expC> is the name of the queue to open. Since the pointer is required to identify an open queue to other messaging functions, always assign the return value to a memory variable. The optional <expN> determines the queue access mode:

<expN>	Access Mode
	If not specified, read-only
0	Read-only
1	Write only. Existing contents are deleted.
2	Append. Text may be added to the end of the existing contents.

The MQCLOSE() function is used to close a queue which has been opened with MQOPEN().

Example

mqdes=mqopen("/myqueue")
if (mqdes < 0)
   messagebox(strerror()+",errno="+alltrim(str(error())))
   return
endif
do while (mqcurmsgs(mqdes) > 0)
   mstr=mqreceive(mqdes)
   if (empty(mstr))
      messagebox(strerror()+",errno="+alltrim(str(error())))
      return
   endif
   messagebox(mstr)
end do
mqclose(mqdes)

Products

Recital, Recital Server