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#define INCL_DOSDEVIOCTL
 
USHORT DosDevIOCtl(pcReceiveQue, 0L, 0x0068, 0x0001, hDevice)
PUSHORT pcReceiveQue;    /* pointer to structure for character count */
HFILE hDevice;           /* device handle                            */
 
The ASYNC_GETINQUECOUNT function retrieves the number of characters in the
receive queue.
 
Parameter     Description
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pcReceiveQue  Points to the RXQUEUE structure that receives the count of
              characters in the receive queue.
 
hDevice       Identifies the serial device that receives the device-control
              function. The handle must have been created previously by
              using the DosOpen function.
 
Return Value
 
The return value is zero if the function is successful or an error value if
an error occurs.
 
Comments
 
The device-driver receive queue is a memory buffer between the memory
pointed to by the read-request packet and the receive hardware for this
serial device. The application may not assume that there are no unsatisfied
read requests if there are characters in the device-driver receive queue.
The behavior of data movement between the read request and the receive queue
may change from release to release of the device driver. Programs should not
be written to have a dependency on this information.
 
Programs should be written to be independent of the receive queue being a
fixed size. The information in this field allows the application to get the
size of the receive queue. The current size of the receive queue is
approximately 1K but is subject to change.
 
The application should be written to avoid device-driver receive queue
overruns by using an application-to-application block protocol with the
system the application is communicating with.
 
See Also
 
DosOpen, ASYNC_GETOUTQUECOUNT, RXQUEUE
 
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