DTWAIN_OpenSource
The DTWAIN_OpenSource function opens a selected Source
DTWAIN_BOOL DTWAIN_OpenSource ( DTWAIN_SOURCE Source );
Parameters Source Specifies a selected TWAIN Source.
Return Values If the function succeeds, TRUE is returned. If the function fails FALSE is returned.
Comments The DTWAIN_OpenSource function opens the DTWAIN_SOURCE Source. When the Source is opened, the application can negotiate any capability that the Source can support, plus other functionality that requires an open Source. The Source provided must have been previously selected by one of the DTWAIN Source Selection Functions.
By default, an application doesn't have to call DTWAIN_OpenSource, since selecting a Source using DTWAIN_SelectSource, DTWAIN_SelectSourceByName, and DTWAIN_SelectDefaultSource will automatically open the Source. However, there are scenarios where the application must call DTWAIN_OpenSource explicitly:
The only case where the application never has to call DTWAIN_OpenSource is the case where once the Source is selected, the next operation is to acquire an image.
There is no harm in repeatedly calling DTWAIN_OpenSource on a Source that is already opened. DTWAIN internally checks for Sources that are already opened, and will not attempt to reopen a Source that is already opened.
TWAIN State Transitions
Prerequisite Function Call(s)
DTWAIN Source Selection Function
See Also |