DTWAIN_SetDeviceNotifications

The DTWAIN_SetDeviceNotifications function sets the device events that the application is allowed to capture.

DTWAIN_BOOL DTWAIN_SetDeviceNotifications (

DTWAIN_SOURCE	Source,
LONG	DeviceValues );

Parameters

Source

An open TWAIN Source.

DeviceValues

A LONG value denoting the device events to capture.

Return Values

The return value is TRUE if successful. Otherwise FALSE is returned.

Comments

The DTWAIN_SetDeviceNotifications function sets up an application to capture device events sent by the Source. The Source Source must be selected using one of the Source Selection Functions.

The DeviceValues specifies which device events to capture. The values that DTWAIN uses are equivalent to the TWAIN 1.8 specification values for these events plus 1. The following values can be combined by using the bitwise OR operator or by adding the desired values (if your development language does not have a bitwise OR):

Value	Meaning
DTWAIN_DE_CHKAUTOCAPTURE	The automatic capture settings on the device have been changed.
DTWAIN_DE_CHKBATTERY	Status of the battery has changed.
DTWAIN_DE_CHKDEVICEONLINE	The device may have been powered off.
DTWAIN_DE_CHKFLASH	The flash setting has changed.
DTWAIN_DE_CHKPOWERSUPPLY	The power supply has changed.
DTWAIN_DE_CHKRESOLUTION	The resolution of the device has changed.
DTWAIN_DE_DEVICEADDED	A device has been added to the Source.
DTWAIN_DE_DEVICEOFFLINE	The device has become unavailable. The device is assumed to be connected.
DTWAIN_DE_DEVICEREADY	A device is ready to capture another image.
DTWAIN_DE_DEVICEREMOVED	A device has been removed from the Source.
DTWAIN_DE_DEVICEOFFLINE	The device is off-line.
DTWAIN_DE_PAPERDOUBLEFEED	Report a double feed to the application.
DTWAIN_DE_PAPERJAM	Report a paper jam to the application.

The DTWAIN_IsCapSupported function can be used to test if device events are supported by the Source. The capability, DTWAIN_CV_CAPDEVICEEVENT is used as the cap to test. Even though DTWAIN always checks if the capability is supported when DTWAIN_SetDeviceNotifications function is called, an application will be able to determine itself whether a Source can perform device events.

For more information on device events, see the topic Capturing Source Device Events.

TWAIN State Transitions

The Source must be in State 4. or higher

Prerequisite Function Call(s)

DTWAIN_SysInitialize

DTWAIN Source Selection Function