References ▼
typedef struct _LTWAINPROPERTYQUERY{L_UINT uStructSize;L_UINT uType;union{pTW_ONEVALUE pltwOneValue;pTW_RANGE pltwRange;pTW_ENUMERATION pltwEnumeration;pTW_ARRAY pltwArray;};} LTWAINPROPERTYQUERY, * pLTWAINPROPERTYQUERY;
The LTWAINPROPERTYQUERY structure provides information about the capability properties.
| Member | Description | |
| uStructSize | Size of the LTWAINPROPERTYQUERY structure, in bytes, for versioning. Use the sizeof() macro to calculate the value. | |
| uType | Holds the type of pointer to use from the union. Possible values are (according to the TWAIN 1.9 specification): | |
| Value | Meaning | |
| TWON_ONEVALUE | The container is of type TW_ONEVALUE and only the pltwOneValue pointer is used. | |
| TWON_RANGE | The container is of type TW_RANGE and only the pltwRange pointer is used. | |
| TWON_ONEVALUE | The container is of type TW_ENUMERATION and only the pltwEnumeration pointer is used. | |
| TWON_ONEVALUE | The container is of type TW_ARRAY and only the pltwArray pointer is used. | |
| pltwOneValue | Pointer to a TW_ONEVALUE structure. | |
| pltwRange | Pointer to a TW_RANGE structure. | |
| pltwEnumeration | Pointer to a TW_ENUMERATION structure. | |
| pltwArray | Pointer to a TW_ARRAY structure. | |
pLTWAINPROPERTYQUERY is a pointer to a LTWAINPROPERTYQUERY structure. Where the function parameter type is pLTWAINPROPERTYQUERY, you can declare an LTWAINPROPERTYQUERY variable, update the structure's fields, and pass the variable's address in the parameter. Declaring a pLTWAINPROPERTYQUERY variable is necessary only if your program requires a pointer.
LTWAINPROPERTIES is allocated by the LTwain::QueryProperty function and freed by LTwain::FreePropQueryStructure function.