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SCardGetAttrib

  • Article

This function gets the current reader attributes for the specified handle. It does not affect the state of the reader, driver, or card.

LONG SCardGetAttrib(
  SCARDHANDLE hCard, 
  DWORD dwAttrId, 
  LPBYTE pbAttr, 
  LPDWORD pcbAttrLen 
);

Parameters

  • hCard
    [in] Handle to the reference value returned from SCardConnect.
  • dwAttrId
    [in] Supplies the identifier for the attribute to get. The following table shows possible values for dwAttrId. These values are read-only. Note that vendors may not support all attributes.
    Value Description
    SCARD_ATTR_ATR_STRING Answer to reset (ATR) string.
    SCARD_ATTR_CHANNEL_ID DWORD encoded as 0xDDDDCCCC, where DDDD = data channel type and CCCC = channel number. The following encodings are defined for DDDD:
    • 0x01 serial I/O; CCCC is a port number.
    • 0x02 parallel I/O; CCCC is a port number.
    • 0x04 PS/2 keyboard port; CCCC is zero.
    • 0x08 SCSI; CCCC is SCSI ID number.
    • 0x10 IDE; CCCC is device number.
    • 0x20 USB; CCCC is device number.
    • 0xFy vendor-defined interface with y in the range 0 through 15; CCCC is vendor defined.
    SCARD_ATTR_CHARACTERISTICS DWORD indicating which mechanical characteristics are supported. If zero, no special characteristics are supported. Note that multiple bits can be set:
    • 0x00000001 Card swallowing mechanism
    • 0x00000002 Card ejection mechanism
    • 0x00000004 Card capture mechanism

    All other values are reserved for future use (RFU).
    SCARD_ATTR_CURRENT_BWT Current block waiting time.
    SCARD_ATTR_CURRENT_CLK Current clock rate, in kHz.
    SCARD_ATTR_CURRENT_CWT Current character waiting time.
    SCARD_ATTR_CURRENT_D Bit rate conversion factor.
    SCARD_ATTR_CURRENT_EBC_ENCODING Current error block control encoding.

    0 = longitudinal redundancy check (LRC)

    1 = cyclical redundancy check (CRC)
    SCARD_ATTR_CURRENT_F Clock conversion factor.
    SCARD_ATTR_CURRENT_IFSC Current byte size for information field size card.
    SCARD_ATTR_CURRENT_IFSD Current byte size for information field size device.
    SCARD_ATTR_CURRENT_N Current guard time.
    SCARD_ATTR_CURRENT_PROTOCOL_TYPE DWORD encoded as 0x0rrrpppp where rrr is RFU and should be 0x000. pppp encodes the current protocol type. Whichever bit has been set indicates which ISO protocol is currently in use. (For example, if bit 0 is set, T=0 protocol is in effect.)
    SCARD_ATTR_CURRENT_W Current work waiting time.
    SCARD_ATTR_DEFAULT_CLK Default clock rate, in kHz.
    SCARD_ATTR_DEFAULT_DATA_RATE Default data rate, in bps.
    SCARD_ATTR_DEVICE_FRIENDLY_NAME Reader's friendly name.
    SCARD_ATTR_DEVICE_IN_USE Reserved for future use.
    SCARD_ATTR_DEVICE_SYSTEM_NAME Reader's system name.
    SCARD_ATTR_DEVICE_UNIT Instance of this vendor's reader attached to the computer. The first instance will be device unit 0, the next will be unit 1 (if it is the same brand of reader) and so on. Two different brands of readers will both have 0 for this value.
    SCARD_ATTR_ICC_INTERFACE_STATUS Single byte. 0 if smart card electrical contact is not active; non-zero if contact is active.
    SCARD_ATTR_ICC_PRESENCE Single byte indicating smart card presence:

    0 = not present

    1 = card present but not swallowed (applies only if reader supports smart card swallowing)

    2 = card present (and swallowed if reader supports smart card swallowing)

    4 = card confiscated
    SCARD_ATTR_ICC_TYPE_PER_ATR Single byte indicating smart card type:

    0 = unknown type

    1 = 7816 Asynchronous

    2 = 7816 Synchronous

    Other values RFU.
    SCARD_ATTR_MAX_CLK Maximum clock rate, in kHz.
    SCARD_ATTR_MAX_DATA_RATE Maximum data rate, in bps.
    SCARD_ATTR_MAX_IFSD Maximum bytes for information file size device.
    SCARD_ATTR_POWER_MGMT_SUPPORT 0 if device does not support power down while smart card is inserted. Non-zero otherwise.
    SCARD_ATTR_PROTOCOL_TYPES DWORD encoded as 0x0rrrpppp where rrr is RFU and should be 0x000. pppp encodes the supported protocol types. A 1 in a given bit position indicates support for the associated ISO protocol, so if bits 0 and 1 are set, both T=0 and T=1 protocols are supported.
    SCARD_ATTR_VENDOR_IFD_SERIAL_NO Vendor-supplied interface device serial number.
    SCARD_ATTR_VENDOR_IFD_TYPE Vendor-supplied interface device type (model designation of reader).
    SCARD_ATTR_VENDOR_IFD_VERSION Vendor-supplied interface device version (DWORD in the form 0xMMmmbbbb where MM = major version, mm = minor version, and bbbb = build number).
    SCARD_ATTR_VENDOR_NAME Vendor name.
  • pbAttr
    [out] Pointer to a buffer that receives the attribute whose identifier is supplied in dwAttrId. If this value is NULL, SCardGetAttrib ignores the buffer length supplied in pcbAttrLen, writes the length of the buffer that would have been returned if this parameter had not been NULL to pcbAttrLen, and returns a success code.
  • pcbAttrLen
    [in, out] Pointer to the length of the pbAttr buffer in bytes; receives the actual length of the received attribute.

Return Values

The following table shows the possible return values.

Value Description
SCARD_S_SUCCESS Succeeds
An error value (see Smart Card Error Values for a list of all error values). Fails

Remarks

SCardGetAttrib is a direct card access function.

Requirements

OS Versions: Windows CE 3.0 and later.
Header: Winscard.h.
Link Library: Winscard.lib.

See Also

SCardConnect | SCardSetAttrib

 Last updated on Saturday, April 10, 2004

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