Thanks Eric. Then you mean in this case, no way to detect it using the scard
API? What is PnP really? Sorry:(

Jianguo

----- Original Message -----
From: "Eric Perlin" <ericperlwindows.microsoft.com>
To: "Jianguo Wang" <jwangbiometricgroup.com>;
<SmartCardSDKDISCUSS.MICROSOFT.COM>
Sent: Tuesday, February 18, 2003 2:03 PM
Subject: RE: How to check the reader status?

> Hmm, another possibility is that the disconnected readers that you see
> are not PnP readers.
> The OS has no way to know if non PnP devices are connected or not.
>
> Eric Perlin [MS]
>
> -----Original Message-----
> From: Jianguo Wang [mailto:jwangBIOMETRICGROUP.COM]
> Sent: Tuesday, February 18, 2003 9:53 AM
> To: SmartCardSDKDISCUSS.MICROSOFT.COM
> Subject: Re: How to check the reader status?
>
>
> Thanks. Here are the codes I used :
> -------------------------
> lReturn = SCardEstablishContext(SCARD_SCOPE_USER,
> NULL,
> NULL,
> &hSC );
> if ( SCARD_S_SUCCESS != lReturn )
> {
> printf("Failed SCardEstablishContext\n");
> exit(1);
> }
>
> // Determine which readers are available.
> lReturn = SCardListReaders(hSC,
> NULL,
> (LPTSTR)&szReaders,
> &cchReaders );
> if ( SCARD_S_SUCCESS != lReturn )
> {
> printf("Failed SCardListReaders\n");
> exit(1);
> }
> -----------------
>
> Without any card connected, I still can get the reader name from
> szReaders.
> So anything wrong with my codes?
>
> Thanks a lot!!
>
> Jianguo
> ----- Original Message -----
> From: "Eric Perlin" <ericperlwindows.microsoft.com>
> To: "Jianguo Wang" <jwangbiometricgroup.com>;
> <SmartCardSDKDISCUSS.MICROSOFT.COM>
> Sent: Tuesday, February 18, 2003 12:29 PM
> Subject: RE: How to check the reader status?
>
>
> > That's TRUE only if you use a NULL SCARDCONTEXT.
> > Specify a real SCARDCONTEXT (obtained from SCardEstablishContext) and
> > you will only get the connected readers.
> >
> > Eric Perlin [MS]
> >
> > -----Original Message-----
> > From: Jianguo Wang [mailto:jwangBIOMETRICGROUP.COM]
> > Sent: Tuesday, February 18, 2003 9:13 AM
> > To: SmartCardSDKDISCUSS.MICROSOFT.COM
> > Subject: Re: How to check the reader status?
> >
> >
> > Thanks. But to my test, seems SCardListReaders will list all the
> > reeaders
> > installed on the machine no matter whether some is still connected.
> >
> > Jianguo
> > ----- Original Message -----
> > From: "Gu Haiming" <cret-ghm163.COM>
> > To: <SmartCardSDKDISCUSS.MICROSOFT.COM>
> > Sent: Tuesday, February 18, 2003 2:29 AM
> > Subject: Re: How to check the reader status?
> >
> >
> > > If on win2k or winXP, SCardListReaders returns the readers connected
> > to PC
> > > currently.
> > >
> > > But on win98, it returns all readers connected now and used to be
> > connected
> > > before to the PC. So you must use SCardGetStatusChange to get the
> > state of
> > > readers.
> > >
> > >
> > > On Mon, 17 Feb 2003 10:54:21 -0800, Eric Perlin
> > > <ericperlWINDOWS.MICROSOFT.COM> wrote:
> > >
> > > >Consider SCardListReaders.
> > > >I also suggest you browse through all Scard APIs to get an idea of
> > what
> > > >each can do.
> > > >
> > > >Eric Perlin [MS]
> > > >
> > > >-----Original Message-----
> > > >From: Jianguo Wang [mailto:jwangBIOMETRICGROUP.COM]
> > > >Sent: Friday, February 14, 2003 8:02 AM
> > > >To: SmartCardSDKDISCUSS.MICROSOFT.COM
> > > >Subject: How to check the reader status?
> > > >
> > > >
> > > >Hi All,
> > > >
> > > >Now I need check the reader status at the beginning of my program.
> > > >Anyone has some hint for it? I mean how do I know which reader
> > > >(hardware) is really connected to my machine?
> > > >
> > > >Thanks for any comment!
> > > >
> > > >Have a great weekend.
> > > >
> > > >Jianguo
> > >
> >
>

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