National Instruments 321645c-01 用户手册

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Chapter 2
Function Reference — DIG_Block_Check
©
 National Instruments Corporation
2-147
NI-DAQ FRM for PC Compatibles
DIG_Block_Check
Format
status = DIG_Block_Check (deviceNumber, group, remaining)
Purpose
Returns the number of items remaining to be transferred after a 
DIG_Block_In
 or 
DIG_Block_Out
 call.
Parameters
Input
Output
Parameter Discussion
group is the group involved in the asynchronous transfer.
Range:
1 or 2 for most devices.
1 through 8 for the DIO-96.
remaining is the number of items yet to be transferred. The actual number of bytes remaining 
to be transferred is equal to remaining multiplied by the value of groupSize specified in the 
call to 
DIG_Grp_Config
 or 
DIG_SCAN_Setup
.
Note
C Programmers:—remaining is a pass-by-reference parameter.
Using This Function
DIG_Block_Check
 monitors an asynchronous transfer of data started via a 
DIG_Block_In
 
or 
DIG_Block_Out
 call. If NI-DAQ has completed the transfer, 
DIG_Block_Check
 
automatically calls 
DIG_Block_Clear
, which permits NI-DAQ to make a new block transfer 
call immediately.
Name
Type
Description
deviceNumber
i16
assigned by configuration utility
group
i16
group
Name
Type
Description
remaining
u32
number of items yet to be transferred