PROPVARIANT

Artículo
11/18/2015

A version of this page is also available for

4/8/2010

This structure is used to define the type tag and the value of a property in a property set. There are five members. The first member, the value-type tag, and the last member, the value of the property, are significant. The middle three members are reserved for future use.

Note

The bool member in previous definitions of this structure has been renamed to boolVal, because some compilers now recognize bool as a keyword.

Note

The PROPVARIANT structure, defined below, includes types that can be serialized in the version 1 property set serialization format. The version 1 format supports all types allowed in the version 0 format plus some additional types. The added types include "Version 1" in the comment field below. Use these types only if a version 1 property set is intended.

Syntax

typedef struct PROPVARIANT {
  VARTYPE vt;
  WORD    wReserved1;
  WORD    wReserved2;
  WORD    wReserved3;
  union {
    CHAR              cVal;
    UCHAR             bVal;
    SHORT             iVal; 
    USHORT            uiVal;
    LONG              lVal; 
    ULONG             ulVal;
    INT               intVal;
    UINT              uintVal;
    LARGE_INTEGER     hVal;
    ULARGE_INTEGER    uhVal;
    FLOAT             fltVal;
    DOUBLE            dblVal;
    VARIANT_BOOL      boolVal;
    SCODE             scode; 
    CY                cyVal;
    DATE              date;
    FILETIME          filetime;
    CLSID*            puuid;
    CLIPDATA*         pclipdata;
    BSTR              bstrVal;
    BSTRBLOB          bstrblobVal;
    BLOB              blob;
    LPSTR             pszVal;
    LPWSTR            pwszVal;
    IUnknown*         punkVal;
    IDispatch*        pdispVal;
    IStream*          pStream; 
    IStorage*         pStorage;
    LPVERSIONEDSTREAM pVersionedStream;
    LPSAFEARRAY       parray;
    CAC               cac;
    CAUB              caub;
    CAI               cai;
    CAUI              caui;
        CAL               cal;
    CAUL              caul;
    CAH               cah;
    CAUH              cauh;
    CAFLT             caflt;
    CADBL             cadbl; 
    CABOOL            cabool; 
    CASCODE           cascode;
    CACY              cacy;
    CADATE            cadate;
    CAFILETIME        cafiletime;
    CACLSID           cauuid;
    CACLIPDATA        caclipdata;
    CABSTR            cabstr;
    CABSTRBLOB        cabstrblob;
    CALPSTR           calpstr;
    CALPWSTR          calpwstr;
    CAPROPVARIANT     capropvar;
    CHAR*             pcVal;
    UCHAR*            pbVal;
    SHORT*            piVal;
    USHORT*           puiVal;
    LONG*             plVal;
    ULONG*            pulVal;
    INT*              pintVal;
    UINT*             puintVal;
    FLOAT*            pfltVal;
    DOUBLE*           pdblVal;
    VARIANT_BOOL*     pboolVal;
    DECIMAL*          pdecVal;
    SCODE*            pscode;
    CY*               pcyVal;
    DATE*             pdate;
    BSTR*             pbstrVal;
    IUnknown**        ppunkVal;
    IDispatch**       ppdispVal;
    LPSAFEARRAY*      pparray;
    PROPVARIANT*      pvarVal;
  };
} PROPVARIANT;

Parameters

vt
Value type tag.

wReserved1
Reserved for future use.

wReserved2
Reserved for future use.

wReserved3
Reserved for future use.

cVal
VT_I1, Version 1

bVal
VT_UI1

iVal
VT_I2

uiVal
VT_UI2

lVal
VT_I4

ulVal
VT_UI4

intVal
VT_INT, Version 1

uintVal
VT_UINT, Version 1

hVal
VT_I8

uhVal
VT_UI8

fltVal
VT_R4

dblVal
VT_R8

boolVal
VT_BOOL

scode
VT_ERROR

cyVal
VT_CY

date
VT_DATE

filetime
VT_FILETIME

puuid
VT_CLSID

pclipdata
VT_CF

bstrVal
VT_BSTR

bstrblobVal
VT_BSTR_BLOB

blob
VT_BLOB, VT_BLOBOBJECT

pszVal
VT_LPSTR

pwszVal
VT_LPWSTR

punkVal
VT_UNKNOWN

pdispVal
VT_DISPATCH

pStream
VT_STREAM, VT_STREAMED_OBJECT

pStorage
VT_STORAGE, VT_STORED_OBJECT

pVersionedStream
VT_VERSIONED_STREAM

parray
VT_ARRAY | VT_*, Version 1

cac
VT_VECTOR | VT_I1, Version 1

caub
VT_VECTOR | VT_UI1

cai
VT_VECTOR | VT_I2

caui
VT_VECTOR | VT_UI2

cal
VT_VECTOR | VT_I4

caul
VT_VECTOR | VT_UI4

cah
VT_VECTOR | VT_I8

cauh
VT_VECTOR | VT_UI8

caflt
VT_VECTOR | VT_R4

cadbl
VT_VECTOR | VT_R8

cabool
VT_VECTOR | VT_BOOL

cascode
VT_VECTOR | VT_ERROR

cacy
VT_VECTOR | VT_CY

cadate
VT_VECTOR | VT_DATE

cafiletime
VT_VECTOR | VT_FILETIME

cauuid
VT_VECTOR | VT_CLSID

caclipdata
VT_VECTOR | VT_CF

cabstr
VT_VECTOR | VT_BSTR

cabstrblob
VT_VECTOR | VT_BSTR_BLOB

calpstr
VT_VECTOR | VT_LPSTR

calpwstr
VT_VECTOR | VT_LPWSTR

capropvar
VT_VECTOR | VT_VARIANT

pcVal
VT_BYREF | VT_I1, Version 1

pbVal
VT_BYREF | VT_UI1, Version 1

piVal
VT_BYREF | VT_I2, Version 1

puiVal
VT_BYREF | VT_UI2, Version 1

plVal
VT_BYREF | VT_I4, Version 1

pulVal
VT_BYREF | VT_UI4, Version 1

pintVal
VT_BYREF | VT_INT, Version 1

puintVal
VT_BYREF | VT_UINT, Version 1

pfltVal
VT_BYREF | VT_R4, Version 1

pdblVal
VT_BYREF | VT_R8, Version 1

pboolVal
VT_BYREF | VT_BOOL, Version 1

pdecVal
VT_BYREF | VT_DECIMAL, Version 1

pscode
VT_BYREF | VT_ERROR, Version 1

pcyVal
VT_BYREF | VT_CY, Version 1

pdate
VT_BYREF | VT_DATE, Version 1

pbstrVal
VT_BYREF | VT_BSTR, Version 1

ppunkVal
VT_BYREF | VT_UNKNOWN, Version 1

ppdispVal
VT_BYREF | VT_DISPATCH, Version 1

pparray
VT_BYREF | VT_ARRAY, Version 1

pvarVal
VT_BYREF | VT_VARIANT, Version 1

Remarks

The PROPVARIANT structure can also hold a value of VT_DECIMAL:

    DECIMAL       decVal;        //VT_DECIMAL

However, the value of the DECIMAL structure requires special handling. The DECIMAL structure is the same size as an entire PROPVARIANT structure and does not fit into the union that holds all other types of values. Instead, the value of the DECIMAL structure occupies the entire PROPVARIANT structure, including the reserved fields and the vt member. However, the first member of the DECIMAL structure is not used and is equal in size to the vt member of the PROPVARIANT structure. Therefore, the PROPVARIANT structure declaration in the propidl.h header file defines the decVal member in such a way that it corresponds to the beginning of the PROPVARIANT structure. Therefore, to put the value of the DECIMAL structure into a PROPVARIANT structure, the value must be loaded into the decVal member and the vt member is set to VT_DECIMAL, just as for any other value.

The data type PROPVARIANT is related to the data type VARIANT, defined as part of Automation in OLE2. Several definitions are reused from Automation, as follows:

typedef struct  tagCY {
    unsigned long      Lo;
    long               Hi;
    } CY;
 
typedef struct  tagDEC {
    USHORT             wReserved;
    BYTE               scale;
    BYTE               sign;
    ULONG              Hi32;
    ULONGLONG          Lo64;
    } DECIMAL;
 
typedef struct  tagSAFEARRAYBOUND {
    ULONG              cElements;
    LONG               lLbound;
    } SAFEARRAYBOUND;
 
typedef struct  tagSAFEARRAY {
    USHORT             cDims;
    USHORT             fFeatures;
    ULONG              cbElements;
    ULONG              cLocks;
    PVOID              pvData;
    SAFEARRAYBOUND     rgsabound [ * ];
    } SAFEARRAY;
 
typedef CY             CURRENCY;
typedef short          VARIANT_BOOL;
typedef unsigned short VARTYPE;
typedef double         DATE;
typedef OLECHAR*       BSTR;

In addition, some types are unique to the PROPVARIANT structure:

typedef struct  tagCLIPDATA {
    // cbSize is the size of the buffer pointed to 
    // by pClipData, plus sizeof(ulClipFmt)
    ULONG              cbSize;
    long               ulClipFmt;
    BYTE*              pClipData;
    } CLIPDATA;

Among the unique PROPVARIANT types are several data types that define counted arrays of other data types. The data types of all counted arrays begin with the letters CA, for example CAUB, and have an OR operator vt value (the VarType of the element and an OR operator with VT_VECTOR). The counted array structure has the following form (where name is the specific name of the counted array).

#define TYPEDEF_CA(type, name) 
typedef struct tag ## name {\
        ULONG cElems;\
        type *pElems;\
        } name

Propvariant type	Code	PROPVARIANT Member	Value Representation
VT_EMPTY	0	None	A property with a type indicator of VT_EMPTY has no data associated with it; that is, the size of the value is zero.
VT_NULL	1	None	This is like a pointer to NULL.
VT_I1	16	cVal	1-byte signed integer.
VT_UI1	17	bVal	1-byte unsigned integer.
VT_I2	2	iVal	Two bytes representing a 2-byte signed integer value.
VT_UI2	18	uiVal	2-byte unsigned integer.
VT_I4	3	lVal	4-byte signed integer value.
VT_UI4	19	ulVal	4-byte unsigned integer.
VT_INT	22	intVal	4-byte signed integer value (equivalent to VT_I4).
VT_UINT	23	uintVal	4-byte unsigned integer (equivalent to VT_UI4).
VT_I8	20	hVal	8-byte signed integer.
VT_UI8	21	uhVal	8-byte unsigned integer.
VT_R4	4	fltVal	32-bit IEEE floating point value.
VT_R8	5	dblVal	64-bit IEEE floating point value.
VT_BOOL	11	boolVal (bool in earlier designs)	Boolean value, a WORD containing 0 (FALSE) or -1 (TRUE).
VT_ERROR	10	scode	A DWORD containing a status code.
VT_CY	6	cyVal	8-byte two's complement integer (scaled by 10,000). This type is commonly used for currency amounts.
VT_DATE	7	date	A 64-bit floating point number representing the number of days (not seconds) since December 31, 1899. For example, January 1, 1900, is 2.0, January 2, 1900, is 3.0, and so on). This is stored in the same representation as VT_R8.
VT_FILETIME	64	filetime	64-bit FILETIME structure. It is recommended that all times be stored in Universal Coordinate Time (UTC).
VT_CLSID	72	puuid	Pointer to a class identifier (CLSID) (or other globally unique identifier (GUID)).
VT_CF	71	pclipdata	Pointer to a CLIPDATA structure, described above.
VT_BSTR	8	bstrVal	Pointer to a null-terminated Unicode string. The string is immediately preceded by a DWORD representing the byte count, but bstrVal points past this DWORD to the first character of the string. BSTRs must be allocated and freed using the Automation SysAllocString and SysFreeString calls.
VT_BSTR_BLOB	0xfff	bstrblobVal	For system use only.
VT_BLOB	65	blob	DWORD count of bytes, followed by that many bytes of data. The byte count does not include the four bytes for the length of the count itself; an empty blob member would have a count of zero, followed by zero bytes. This is similar to the value VT_BSTR, but does not guarantee a null byte at the end of the data.
VT_BLOBOBJECT	70	blob	A blob member containing a serialized object in the same representation that would appear in VT_STREAMED_OBJECT. That is, a DWORD byte count (where the byte count does not include the size of itself) which is in the format of a class identifier followed by initialization data for that class.
			The only significant difference between VT_BLOB_OBJECT and VT_STREAMED_OBJECT is that the former does not have the system-level storage overhead that the latter would have, and is therefore more suitable for scenarios involving numbers of small objects.
VT_LPSTR	30	pszVal	Pointer to a null-terminated ANSI string in the system default code page.
VT_LPWSTR	31	pwszVal	Pointer to a null-terminated Unicode string in the user's default locale.
VT_UNKNOWN	13	punkVal	New
VT_DISPATCH	9	pdispVal	New
VT_STREAM	66	pStream	Pointer to an IStream interface, representing a stream which is a sibling to the "Contents" stream.
VT_STREAMED_OBJECT	68	pStream	As in VT_STREAM, but indicates that the stream contains a serialized object, which is a CLSID followed by initialization data for the class. The stream is a sibling to the "Contents" stream that contains the property set.
VT_STORAGE	67	pStorage	Pointer to an IStorage interface, representing a storage object that is a sibling to the "Contents" stream.
VT_STORED_OBJECT	69	pStorage	As in VT_STORAGE, but indicates that the designated IStorage contains a loadable object.
VT_VERSIONED_STREAM	73	pVersionedStream	A stream with a GUID version.
VT_DECIMAL	14	decVal	A DECIMAL structure.
VT_VECTOR	0x1000	ca*	If the type indicator is combined with VT_VECTOR by using an OR operator, the value is one of the counted array values. This creates a DWORD count of elements, followed by a pointer to the specified repetitions of the value.
			For example, a type indicator of VT_LPSTR\|VT_VECTOR has a DWORD element count, followed by a pointer to an array of LPSTR elements.
			VT_VECTOR can be combined by an OR operator with the following types: VT_I1, VT_UI1, VT_I2, VT_UI2, VT_BOOL, VT_I4, VT_UI4, VT_R4, VT_R8, VT_ERROR, VT_I8, VT_UI8, VT_CY, VT_DATE, VT_FILETIME, VT_CLSID, VT_CF, VT_BSTR, VT_LPSTR, VT_LPWSTR, and VT_VARIANT. VT_VECTOR can also be combined by an OR operation with VT_BSTR_BLOB, however it is for system use only.
VT_ARRAY	0x2000	Parray	If the type indicator is combined with VT_ARRAY by an OR operator, the value is a pointer to a SAFEARRAY. VT_ARRAY can use the OR with the following data types: VT_I1, VT_UI1, VT_I2, VT_UI2, VT_I4, VT_UI4, VT_INT, VT_UINT, VT_R4, VT_R8, VT_BOOL, VT_DECIMAL, VT_ERROR, VT_CY, VT_DATE, VT_BSTR, VT_DISPATCH, VT_UNKNOWN, and VT_VARIANT. VT_ARRAY cannot use OR with VT_VECTOR.
VT_BYREF	0x4000	p*	If the type indicator is combined with VT_BYREF by an OR operator, the value is a reference. Reference types are interpreted as a reference to data, similar to the reference type in C++ (for example, "int&").
			VT_BYREF can use OR with the following types: VT_I1, VT_UI1, VT_I2, VT_UI2, VT_I4, VT_UI4, VT_INT, VT_UINT, VT_R4, VT_R8, VT_BOOL, VT_DECIMAL, VT_ERROR, VT_CY, VT_DATE, VT_BSTR, VT_UNKNOWN, VT_DISPATCH, VT_ARRAY, and VT_VARIANT.
VT_VARIANT	12	capropvar	A DWORD type indicator followed by the corresponding value. VT_VARIANT can be used only with VT_VECTOR or VT_BYREF.
VT_TYPEMASK	0xFFF		Used as a mask for VT_VECTOR and other modifiers to extract the raw VT value.

Requirements

Header	oaidl.h
Windows Embedded CE	Windows CE 2.0 and later
Windows Mobile	Windows Mobile Version 5.0 and later

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PROPVARIANT

Syntax

Parameters

Remarks

Requirements

See Also

Reference

Other Resources

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