wiasReadPropStr function (wiamdef.h)

The wiasReadPropStr function retrieves a string property value from a WIA item.

Syntax

HRESULT wiasReadPropStr(
  [in]            BYTE   *pWiasContext,
                  PROPID propid,
  [out]           BSTR   *pbstr,
  [out, optional] BSTR   *pbstrOld,
                  BOOL   bMustExist
);

Parameters

[in] pWiasContext

Pointer to a WIA item context.

propid

Specifies the property identifier.

[out] pbstr

Pointer to a memory location that receives the first byte of the property's string value.

[out, optional] pbstrOld

Pointer to a memory location that receives the first byte of the property's previous value. If this information is not needed, set this parameter to NULL.

bMustExist

Indicates whether the property must exist. If set to TRUE, the property must exist; if set to FALSE, the property does not have to exist.

Return value

On success, the function returns S_OK. If the function fails, it returns a standard COM error or one of the WIA_ERROR_XXX errors (described in the Microsoft Windows SDK documentation).

Remarks

When the minidriver has completed using the string it received from this function, it must deallocate the memory used for the string.

Requirements

See also

wiasReadPropBin

wiasReadPropFloat

wiasReadPropGuid

wiasReadPropLong

wiasWritePropStr