DTWAIN_ARRAY Storage Types

There are different DTWAIN_ARRAY types that depend on the type of data that each one stores. A DTWAIN_ARRAY may contain a sequence of integers, floating point values, DTWAIN_SOURCE's, Strings, and other data types. When a DTWAIN_ARRAY is initialized by the application using DTWAIN_ArrayCreate, the data type must also be specified. The supported data types and DTWAIN_ARRAY constants that define each type are as follows:

Data type	DTWAIN_ARRAY constant
DTWAIN_SOURCE	DTWAIN_ARRAYSOURCE
DTWAIN_FLOAT	DTWAIN_ARRAYFLOAT
LONG	DTWAIN_ARRAYLONG
LONG64	DTWAIN_ARRAYLONG64
DTWAIN_STRING	DTWAIN_ARRAYSTRING
LPVOID	DTWAIN_ARRAYANY
DTWAIN_FRAME	DTWAIN_ARRAYFRAME
HANDLE	DTWAIN_ARRAYHANDLE
DTWAIN_BOOL	DTWAIN_ARRAYLONG
DTWAIN_ANSISTRING	DTWAIN_ARRAYANSISTRING
DTWAIN_WIDESTRING	DTWAIN_ARRAYWIDESTRING

All integer variables are stored as LONGS, including DTWAIN_BOOL. DTWAIN expects the application to always use LONG variables when sending or retrieving integers from a DTWAIN_ARRAY. If not, fatal runtime errors may occur. Whenever your application initializes a DTWAIN_ARRAY, it must specify the type of data the array will store. The DTWAIN_ARRAY constant defined above is used to specify the type.

String types

For string types, DTWAIN_ARRAY will either store 8-bit character types or 16-bit (Unicode or wide) character types. A single DTWAIN_ARRAY cannot hold both string types at the same time. A DTWAIN_ARRAYSTRING will hold either 8-bit or 16-bit character strings, depending on the version of DTWAIN DLL that is used.

For 8-bit character types, DTWAIN_ARRAYANSISTRING can be used. If the DTWAIN DLL used is the ANSI version (DTWAIN32.DLL, DTWAIN64.DLL), then either DTWAIN_ARRAYSTRING or DTWAIN_ARRAYANSISTRING can be used to store 8-bit character strings.

For 16-bit character types, DTWAIN_ARRAYWIDESTRING can be used. If the DTWAIN DLL used is the Unicode version (DTWAIN32U.DLL, DTWAIN64U.DLL), then either DTWAIN_ARRAYSTRING or DTWAIN_ARRAYWIDESTRING can be used to store 16-bit character strings.

You can store Unicode strings in an application that uses the ANSI version of DTWAIN by specifying the type of array as DTWAIN_ARRAYWIDESTRING. Similarly, you can store ANSI strings in an application that uses the Unicode version of DTWAIN by specifying the type of array as DTWAIN_ARRAYANSISTRING.