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4/8/2010

This structure contains information about a message queue.

Syntax 

typedef MSGQUEUEINFO{
  DWORD 
dwSize;
  DWORD 
dwFlags;
  DWORD 
dwMaxMessages;
  DWORD 
cbMaxMessage;
  DWORD 
dwCurrentMessages;
  DWORD 
dwMaxQueueMessages;
  WORD 
wNumReaders;
  WORD 
wNumWriters;
} MSGQUEUEINFO, *PMSGQUEUEINFO, FAR* LPMSGQUEUEINFO;

Members

dwSize

Size of the buffer passed in, larger than sizeof(MSGQUEUEINFO).

dwFlags

Value specified in MSGQUEUEOPTIONS.dwFlagspassed when the message queue is created. Describes the behavior of the message queue. Set to MSGQUEUE_NOPRECOMMIT to allocate message buffers on demand and to free the message buffers after they are read, or set to MSGQUEUE_ALLOW_BROKEN to enable a read or write operation to complete even if there is no corresponding writer or reader present.

dwMaxMessages

Maximum number of messages allowed in queue, if it is zero, then no restriction on the number of messages.

cbMaxMessage

Length of the message in bytes.

dwCurrentMessages

Number of messages currently existing in the queue.

dwMaxQueueMessages

Maximum number of messages that have ever been in the queue at one time.

wNumReaders

Number of readers attached to the queue for reading.

wNumWriters

Number of writers attached to the queue for writing.

Remarks

If dwMaxMessagesis set to zero, there are no restrictions on the number of messages in the queue. This implicitly enables the same behavior as setting MSGQUEUE_NOPRECOMMIT in dwFlags.

If the MSGQUEUE_ALLOW_BROKEN flag is not specified and either the read or write exists, assuming a single read and writer, the queue will be deleted from memory and only the open handle to the queue will exist. The only option at this point is to close the remaining open handle and reopen the queue if necessary.

Requirements

Header msgqueue.h
Windows Embedded CE Windows CE .NET 4.0 and later
Windows Mobile Windows Mobile Version 5.0 and later

See Also