描述:
MSDN里面描述的很少。
请问其含义和使用
看哪方面的书
谢谢高手指点！
解决方案1:
MSDN挺详细
C++ Language Reference
_variant_t ClassSee Also
Compiler COM Support Class Overview
Requirements
Header: comutil.h
Lib: comsupp.lib
Microsoft Specific
A _variant_t object encapsulates the VARIANT data type. The class manages resource allocation and deallocation and makes function calls to VariantInit and VariantClear as appropriate.
Construction
_variant_t Constructs a _variant_t object.
Operations
Attach Attaches a VARIANT object into the _variant_t object.
Clear Clears the encapsulated VARIANT object.
ChangeType Changes the type of the _variant_t object to the indicated VARTYPE.
Detach Detaches the encapsulated VARIANT object from this _variant_t object.
SetString Assigns a string to this _variant_t object.
Operators
operator = Assigns a new value to an existing _variant_t object.
operator ==, != Compare two _variant_t objects for equality or inequality.
Extractors Extract data from the encapsulated VARIANT object.
END Microsoft Specific
Requirements
Header: comutil.h
Lib: comsupp.lib
See Also
Compiler COM Support Class Overview
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解决方案3:VARIANT 数据类型在Windows SDK文档中有详细描述