MQOPEN()

From Lianjapedia
Revision as of 03:57, 10 April 2017 by Yvonne.milne (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Purpose

Open a handle to a message queue

Syntax

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

See Also

JSON_DECODE(), JSON_DECODE_FILE(), JSON_ENCODE(), MQCLOSE(), MQCREATE(), MQCURMSGS(), MQRECEIVE(), MQSEND(), MQSENDMESSAGE(), MQUNLINK(), XML_DECODE(), XML_ENCODE(), XML_GATHER(), XML_SCATTER()

Description

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

<expN> Access Mode
Unspecified Read only access
0 Read only access
1 Write only access
2 Read/Write access

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

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)
enddo
mqclose(mqdes)