About Winscard SCardConnect!

[Guest]

Hi there,

I had 2 questions.

In SCardConnect function in Winscard.h:

extern WINSCARDAPI LONG WINAPI
SCardConnectA(
IN SCARDCONTEXT hContext,
IN LPCSTR szReader,
IN DWORD dwShareMode,
IN DWORD dwPreferredProtocols,
OUT LPSCARDHANDLE phCard,
OUT LPDWORD pdwActiveProtocol);

How do we simulate IN and OUT in C#? I know you can simulate either this:

out keyword

or

[In] attribute

or

[Out] attribute

But there is no In keyword?

And i used DWORD in C# as System.UInt32. I hope it is a right conversion.

[DllImport("winscard.dll", SetLastError=true)]
private static extern int SCardConnectA(UInt32 hContext, String szReader,
UInt32 dwShareMode, UInt32 dwPreferredProtocols, out UInt32 phCard, out
UInt32 pdwActiveProtocol);

Please correct me if i am wrong.

2)

I had some confusion when to use SCardConnectA or SCardConnectW. Unicode and
non unicode, does it makes difference? Can anyone elaborate please?

Below are the codes extracted from Winscard.h:

extern WINSCARDAPI LONG WINAPI
SCardConnectA(
IN SCARDCONTEXT hContext,
IN LPCSTR szReader,
IN DWORD dwShareMode,
IN DWORD dwPreferredProtocols,
OUT LPSCARDHANDLE phCard,
OUT LPDWORD pdwActiveProtocol);
extern WINSCARDAPI LONG WINAPI
SCardConnectW(
IN SCARDCONTEXT hContext,
IN LPCWSTR szReader,
IN DWORD dwShareMode,
IN DWORD dwPreferredProtocols,
OUT LPSCARDHANDLE phCard,
OUT LPDWORD pdwActiveProtocol);
#ifdef UNICODE
#define SCardConnect SCardConnectW
#else
#define SCardConnect SCardConnectA
#endif // !UNICODE

Thanks.