How To Create And Use The Adc Com Interfaces; Read-Ahead Bar Code Data Access - Intermec 700 Series 700 User Manual

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Chapter 6 Scanner Support

How to Create and Use the ADC COM Interfaces

ITC_BARCODE_DATA_DETAILS stBCDetails;
BYTE rgbBCData[1024]; // Buffer used to accept the bar code data
DWORD dwBytesReceived; // Number of bytes in the return data.
HRESULT hrStatus = pIBCControl->Read(
rgbBCData,
sizeof(rgbBCData),
&dwBytesReceived,
& stBCDetails,
INFINITE
);
148
You can also use the Input Device Functions (starting on page 154) to
create and use the ADC COM interfaces.
1 Create and initialize the in-process Bar Code Reader object using
ITCDeviceOpen() (see page 154). This function returns a COM
Interface pointer to the Bar Code Reader Object created by the
function.
2 Set the data grid if data filtering is desired (default grid gives the applica-
tion all the data). See "Grid Data Filtering" on page 149, IADC::SetAt-
tribute() on page 162, and IBarCodeReaderControl::SetAttribute() on
page 172 for more information.
3 Issue a read to accept the bar code data. The timestamp, symbology, and
data type are put into the ITC_BARCODE_DATA_DETAILS struc-
ture. Passing in a pointer to this structure is optional. The following
sample code uses an infinite timeout.
4 Compile and link the application.

Read-Ahead Bar Code Data Access

The Bar Code Reader COM object delivers ADC data to the connection
in read-ahead mode. In this mode, the data is queued until a COM con-
nection is ready to read it. Read-ahead mode decouples reader device per-
formance from the application performance. That is, data is read as fast as
the user can scan it, independent of the connection processing load.
The maximum number of bar codes that can be read by the scanner and
saved, ahead of the application taking the data, is limited by the number of
readahead buffers. For the 700 Monochrome Computer, this limit is
three. The scanned data is not saved for an application until the first
Read() function is posted.
700 Series Monochrome Mobile Computer User's Manual