SCardListInterfacesW function (winscard.h)

Article
02/09/2023

The SCardListInterfaces function provides a list of interfaces supplied by a given card.

The caller supplies the name of a smart card previously introduced to the subsystem, and receives the list of interfaces supported by the card.

Syntax

LONG SCardListInterfacesW(
  [in]      SCARDCONTEXT hContext,
  [in]      LPCWSTR      szCard,
  [out]     LPGUID       pguidInterfaces,
  [in, out] LPDWORD      pcguidInterfaces
);

Parameters

[in] hContext

Handle that identifies the resource manager context for the query. The resource manager context can be set by a previous call to SCardEstablishContext. This parameter cannot be NULL.

[in] szCard

Name of the smart card already introduced to the smart card subsystem.

[out] pguidInterfaces

Array of interface identifiers (GUIDs) that indicate the interfaces supported by the smart card. If this value is NULL, SCardListInterfaces ignores the array length supplied in pcguidInterfaces, returning the size of the array that would have been returned if this parameter had not been NULL to pcguidInterfaces and a success code.

[in, out] pcguidInterfaces

Size of the pcguidInterfaces array, and receives the actual size of the returned array. If the array size is specified as SCARD_AUTOALLOCATE, then pcguidInterfaces is converted to a pointer to a GUID pointer, and receives the address of a block of memory containing the array. This block of memory must be deallocated with SCardFreeMemory.

Return value

This function returns different values depending on whether it succeeds or fails.

Return code	Description
Success	SCARD_S_SUCCESS.
Failure	An error code. For more information, see Smart Card Return Values.

Remarks

This function is not redirected, but calling the function when attempting a Remote Desktop session will not result in an error. It only means that the result will be from the remote computer instead of the local computer.

The SCardListInterfaces function is a database query function. For more information on other database query functions, see Smart Card Database Query Functions.

Examples

The following example shows listing the interfaces for a smart card.

LPGUID          pGuids = NULL;
LONG            lReturn;
DWORD           cGuid = SCARD_AUTOALLOCATE;

// Retrieve the list of interfaces.
lReturn = SCardListInterfaces(NULL,
                              (LPCSTR) "MyCard",
                              (LPGUID)&pGuids,
                              &cGuid );
if ( SCARD_S_SUCCESS != lReturn )
{
    printf("Failed SCardListInterfaces\n");
    exit(1);   // Or other appropriate action
}

if ( 0 != cGuid )
{
    // Do something with the array of Guids.
    // Remember to free pGuids when done (by SCardFreeMemory).
    // ...
}

Note

The winscard.h header defines SCardListInterfaces as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	winscard.h
Library	Winscard.lib
DLL	Winscard.dll