Typedef Declaration in VB

[floydus]

Hi all !
I'm just about to use a DLL made in C++, I'll need some help to declare all "TypeDef" and functions in a vb fashion way.
PLEASE GIVE EXPLANATIONS thankls

The most important for now are the CONNECTION_ADDR type and the NetApiConnect method....

Can you help me to understand how the sruct should be declared in VB, and also the method ?
Here's how I declared the "API function in vb so far...

Private Declare Function NetApiConnect Lib "NetApi" (IN CONNECTION_ADDR * prConnAddr,
IN int nNumConnections) As Long

I'm now posting part of the .h file.

typedef struct {
CONNECTION_TYPE eType;
union {
SOCKET_ADDR rSocket;
MODEM_ADDR rModem;
COMM_PORT_ADDR rCommPort;
GENERIC_ADDR rGeneric;
};
} CONNECTION_ADDR;

typedef int (* LOG_CALLBACK)(
IN int nRid,
IN OB_LOG_ENTRY * prObLogEntry,
IN unsigned long nCallbackParameter
);

typedef enum {
SOCKET_TYPE,
MODEM_TYPE,
COMM_PORT_TYPE,
UNKNOWN_CONN_TYPE,
_LAST_CONN_TYPE
} CONNECTION_TYPE;

typedef struct {
unsigned long ulIpAddress;
char acHost[ MAX_HOST_NAME_LEN ];
unsigned short nPort;
} SOCKET_ADDR;

typedef struct {
char acCallString[64];
} MODEM_ADDR;

typedef struct {
int nPort;
} COMM_PORT_ADDR;

typedef struct {
char acData[ CONNECTION_ADDR_MIN_SIZE ];
} GENERIC_ADDR;



typedef struct _SESSION * SESSION_ID;
typedef struct _REQUEST * REQUEST_ID;
typedef int (* VIDEO_CALLBACK)(
IN int nRid,
IN OB_VIDEO * prObVideo,
IN int nError,
IN SESSION_ID hSessionId,
IN REQUEST_ID hRequestId,
IN unsigned long nCallbackParameter
);
typedef enum {
SEEK_TIME_ABSOLUTE,
SEEK_TIME_LIVE,
SEEK_TIME_BEFORE,
SEEK_TIME_AFTER,
SEEK_NEXT,
SEEK_PREV,
SEEK_GET_TIME,
SEEK_GET_TIME_AND_RID
} SEEK_TYPE;

#define PLAYBACK_REVERSE 0x01
#define PLAYBACK_FRAME_CURRENT 0x02
#define PLAYBACK_FRAME_ALL 0x04
#define PLAYBACK_REAL_TIME 0x08
#define PLAYBACK_NO_DROPS 0x10
#define PLAYBACK_LIVE_MODE 0x20

typedef enum {
CFG_LIVE_MODE_QUALITY,
CFG_VERSION,
CFG_NO_SEEK_ON_CONNECT,
} CONFIG_TYPE;

typedef struct {
char acVersion[64]; // Version label. May or may not be specified.
// Empty string if unspecified.
unsigned long nMajor;
unsigned long nMinor;
unsigned long nPatch;
unsigned long nBuildNo;
} VERSION_INFO;
#undef DLL_DECLSPEC
#ifdef NETAPI_EXPORTS
#define DLL_DECLSPEC __declspec(dllexport)
#else
#define DLL_DECLSPEC __declspec(dllimport)
#endif

DLL_DECLSPEC int
NetApiConnect(
IN CONNECTION_ADDR * prConnAddr,
IN int nNumConnections
);

DLL_DECLSPEC int
NetApiDisconnect(
);

DLL_DECLSPEC int
NetApiGetResources(
OUT OB_RESOURCE ** pprResources,
OUT int * pnNumResources
);

DLL_DECLSPEC int
NetApiGetRid(
IN int nUniqueId,
IN RESOURCE_TYPE eType,
IN int nParameter
);

DLL_DECLSPEC int
NetApiGetObject(
IN int nRid,
IN RVCOBTYPE eObject,
OUT void * pvObject,
IN int nSize,
OUT int * pnPercentRemaining
);

DLL_DECLSPEC int
NetApiSetObject(
IN int nRid,
IN RVCOBTYPE eObject,
IN void * pvObject,
IN int nSize,
OUT int * pnPercentRemaining
);

DLL_DECLSPEC int
NetApiVideoPlay(
IN int * pnRids,
IN int nNumRids,
IN int nMainVideoIndex,
IN VIDEO_CALLBACK pCallback,
IN unsigned long nCallbackParameter,
IN int nFlags
);

DLL_DECLSPEC int
NetApiVideoStop(
);

DLL_DECLSPEC int
NetApiVideoSeek(
IN OUT FILETIME * pnTime,
IN SEEK_TYPE eSeekType,
OUT BOOL * pbSeekHit
);

DLL_DECLSPEC int
NetApiLogUpdateSection(
IN LOG_TYPE eLog,
IN int nFirstEntry,
IN int nNumEntries,
IN LOG_CALLBACK pCallback,
IN unsigned long nCallbackParameter,
IN int nFlags
);

DLL_DECLSPEC int
NetApiLogGetSize(
IN LOG_TYPE eLog
);

DLL_DECLSPEC void
NetApiGetCfg(
IN CONFIG_TYPE eConfigType,
OUT void * pvConfigData,
IN int nConfigSize
);

DLL_DECLSPEC void
NetApiSetCfg(
IN CONFIG_TYPE eConfigType,
OUT void * pvConfigData,
IN int nConfigSize
);

DLL_DECLSPEC int
NetApiGetConnectionStatus(
IN int nConnection,
OUT int * pnLine,
OUT char ** ppcFile,
OUT int * pnExtendedError
);

DLL_DECLSPEC char *
NetApiGetLastErrors(
);

/*
* Undocumented function
*/
DLL_DECLSPEC char *
ErrString(
IN int nErr
);

#ifdef __cplusplus
}
#endif


#endif

[RHelliwell]

I'm not a big C programmer, but you'd normally do something like:

Public Declare Function FunctionName Lib "Library.dll" (ByVal Parameter1 As Integer, ByVal Parameter2 As Integer, ByVal bState As Integer) As Boolean

...inside a module.

BTW - Remember INT in C is a 32-bit data type, where as in VB it's a 16-bit. Maybe you should use SHORT. Oh, and INT in VB is ALWAYS signed.

[floydus]

Well thanks, but I allready know that, if you look at my original post, you'll see the following declaration.
Private Declare Function NetApiConnect Lib "NetApi" (IN CONNECTION_ADDR * prConnAddr,
IN int nNumConnections) As Long

In fact, my post is more about arguments declaration of typedef type to be used by the NetApiConnect function.
In C, it's defined as a typedef struct, and it uses "union", which I don't know how to translate in VB.

Thanks for posting, you help stupid people like me !!!!
Not stupid, but without some specific knowledge.

[RHelliwell]

My bad, i'll read the post properly next time.

[edburdo]

A structure in C is a Type in VB.
And an enum is till an enum.

I don't know about the Union stuff though... If you can find it, Dan Appleman has a book out on translating C++ API's to VB Classic. Pretty good book...

[Phil Weber]

A union says, "Depending on the value of the eType field, this block of memory can be either a SOCKET_ADDR, MODEM_ADDR, COM_PORT_ADDR or GENERIC_ADDR." The C compiler takes care of mapping the memory into the appropriate struct automatically.

VB has no equivalent of a union, but you can simulate one by creating a Type consisting of an eType field and an array of bytes large enough to hold the largest struct. At runtime, read eType to determine what kind of data is in the byte array, the use the CopyMemory API to copy the bytes into a variable of the appropriate Type. You may find some of these discussions helpful: http://groups.google.com/groups/search?q=vb+union+type

[floydus]

Well I do know it's always going to be a "SOCKET_TYPE" connection type.
I've tried the following code, but get no connection to host....
This doesn't work.
' MY FORM CODE....

Private Sub Form_Load()
Dim mytestConnect As ConnectionAddress
Dim mySocket As SocketAddress
Dim test As Long
mySocket.acHost(0) = "1"
mySocket.acHost(1) = "0"
mySocket.acHost(2) = "."
mySocket.acHost(3) = "1"
mySocket.acHost(4) = "."
mySocket.acHost(5) = "1"
mySocket.acHost(6) = "."
mySocket.acHost(7) = "2"
'Do I have to terminate the string or something ?
mySocket.nPort = 82

mytestConnect.eType = 0
mytestConnect.Socket = mySocket
'MsgBox mytestConnect.Socket.acHost(0)
test = NetApiDisconnect()
'MsgBox test
test = NetApiConnect(mytestConnect, 1)
MsgBox test
End Sub

'MY MODULE CODE
Public Type SocketAddress
ulIpAddress As Long
acHost(63) As String * 1 ' will be used by default if set, I will use it e.g. "10.1.1.2"
nPort As Long ' e.g 80
End Type

Public Type ConnectionAddress
eType As Long 'Will always be 0, refers to "SOCKET_TYPE" I think
Socket As SocketAddress
End Type

Public Declare Function NetApiConnect Lib "MyApi.dll" (myAddress As ConnectionAddress, ByVal numberConnections As Long) As Long
Public Declare Function NetApiDisconnect Lib "MyApi.dll" () As Long


I don't even know how I could debug the whole thing....
The dll is responding at least !
It's probably the way I'm passing the string "acHost" ????
You see anything wrong ?

Thanks.

[mstraf]

your definition of acHost is an array of Strings of length one, instead of one string of length 64. Try this:

Public Type SocketAddress
ulIpAddress As Long
acHost As String * 64
nPort As Long ' e.g 80
End Type