Example Of Sending A Command - Socket ScanAPI Reference Manual

Socket ScanAPI Reference
An important point is the fact that a property set or get can fail for many reasons,
and some of them will require the application to retry the operation and some
should just be taken into consideration. For example, if a property returns a
REQUEST TIMEOUT error because the scanner is out of the range for a brief instant
or busy receiving decoded data, having retry logic can fix this issue.

4.7 Example of sending a command

This section describes the steps for sending a command to a device.
Let's imagine an application using ScanAPI has a button on its UI to trigger a scan.
For clarity purposes we assume the application correctly handles the connection of
the scanner and has kept a handle to ScanAPI and to this scanner accessible.
The application has ScanAPI consumer logic that will receive the messages from
ScanAPI.
This consumer logic uses the wait API with the ScanAPI object reference that has
been previously opened with the open API with NULL as device name.
The button handler creates a ScanObject, and fills the Property part with a property
ID set to kSktScanPropIdTriggerDevice, a property type set to byte, and the property
byte value set to kSktScanTriggerStart as explained in the paragraph 14.5 Property
kSktScanPropIdTriggerDevice.
This button handler uses the set API to send this property to the device identified by
its reference. If the return code of this API is successful, the button handler can then
disable the trigger button indicating the trigger is in progress.
The application's ScanAPI consumer logic that was waiting for ScanAPI messages by
using the wait API should receive the Set Complete message with the property ID set
to kSktScanPropIdTriggerDevice.
The result indicates if the trigger worked. At that point the device should have the
aim light turned on and should be ready to scan and decode data. The application
trigger button can then be enabled.
C++ Source code sample:
void CMyAppDlg::OnTriggerButton()
{
SKTRESULT Result=ESKT_NOERROR;
TSktScanObject ScanObj;
memset(&ScanObj,0,sizeof(ScanObj));
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