SCardGetReaderIconW function (winscard.h)

Article
02/22/2024

The SCardGetReaderIcon function gets an icon of the smart card reader for a given reader's name. This function does not affect the state of the card reader.

Syntax

LONG SCardGetReaderIconW(
  [in]      SCARDCONTEXT hContext,
  [in]      LPCWSTR      szReaderName,
  [out]     LPBYTE       pbIcon,
  [in, out] LPDWORD      pcbIcon
);

Parameters

[in] hContext

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

[in] szReaderName

Reader name. You can get this value by calling the SCardListReaders function.

[out] pbIcon

Pointer to a buffer that contains a BLOB of the smart card reader icon as read from the icon file. If this value is NULL, the function ignores the buffer length supplied in the pcbIcon parameter, writes the length of the buffer that would have been returned to pcbIcon if this parameter had not been NULL, and returns a success code.

[in, out] pcbIcon

Length, in characters, of the pbIcon buffer. This parameter receives the actual length of the received attribute. If the buffer length is specified as SCARD_AUTOALLOCATE, then pbIcon is converted from a pointer to a byte pointer and receives the address of a block of memory that contains the attribute. This block of memory must be deallocated with the SCardFreeMemory function.

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

The icon should be 256 × 256 pixels with no alpha channel.

Examples

PBYTE    pbIcon = NULL;
DWORD    cbIcon = SCARD_AUTOALLOCATE;
DWORD    i;
LONG     lReturn;
LPTSTR   szReaderName = "USB Smart Card Reader 0";

// Retrieve the reader's icon.
// hContext was set by a previous call to SCardEstablishContext.
lReturn = SCardGetReaderIcon(hContext,
                         szReaderName,
                         (PBYTE)&pbIcon,
                         &cbIcon);

if ( SCARD_S_SUCCESS != lReturn )
{
    printf("Failed SCardGetReaderIcon - %x\n", lReturn);
    // Take appropriate action.
}
else
{
    // Free the memory when done. 
    lReturn = SCardFreeMemory(hContext, pbIcon);
}

Note

The winscard.h header defines SCardGetReaderIcon 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 8 [desktop apps only]
Minimum supported server	Windows Server 2012 [desktop apps only]
Target Platform	Windows
Header	winscard.h

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