pvargDest, pvargSrc, wFlags, vtNew)
VARIANTARG FAR* pvargDest
VARIANTARG FAR* pvargSrc
unsigned short wFlags
This function converts a variant from one type to another.
Pointer to the VARIANTARG to receive the coerced type.
If this is the same as pvargSrc
, the variant will be converted in place.
Pointer to the source VARIANTARG to be coerced.
Flags that control the coercion.
The only defined flag is VARIANT_NOVALUEPROP, which prevents the function from
attempting to coerce an object to a fundamental type by getting the Value
Applications should set this flag only if necessary, because it makes their
behavior inconsistent with other applications.
The type to coerce to.
If the return code is S_OK, the vt
field of the *pvargDest
will always be the same as this value.
The SCODE obtained from the returned HRESULT is one of the following:
||The variant type vtNew is not a valid type of variant.
||The data pointed to by pvargSrc does not fit in the destination type.
||The argument could not be coerced to the specified type.
||One of the arguments is invalid.
||Memory could not be allocated for the conversion.
function handles coercions between the fundamental types (including
numeric-to-string and string-to-numeric coercions). A variant that has VT_BYREF set is
coerced to a value by fetching the referenced value. An object is coerced to a
value by invoking the object's Value property (DISPID_VALUE).
Typically, the implementor of IDispatch::Invoke
determines which member is being accessed, then calls VariantChangeType
to get the value of one or more arguments.
For example, if the IDispatch
call specifies a SetTitle member that takes one string argument, the
implementor would call VariantChangeType
to attempt to coerce the argument to VT_BSTR.
did not return an error, the argument could then be fetched directly from the bstrVal
field of the VARIANTARG.
returned DISP_E_TYPEMISMATCH, the implementor would set *puArgErr
to 0 (indicating the argument in error) and return DISP_E_TYPEMISMATCH from IDispatch::Invoke
Note that you should not attempt to change the type of a VARIANTARG in the rgvarg
array in place.
Arrays of one type can't be converted to arrays of another type with this
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