SCard FoxPro Reference Documentation
SCard
Current Version: 11.6.0
Chilkat.SCard
Enumerate available PC/SC smart card readers and identify the reader the
application should use.
Connect to a reader/card, check card presence and status, and manage the
active PC/SC connection.
Send APDU commands directly to the card and receive the raw response
bytes and status words.
Issue lower-level reader control commands when supported by the reader
driver and PC/SC environment.
Monitor reader or card status changes so applications can detect card
insertion, removal, or state changes.
Use PC/SC transactions for coordinated card access and inspect detailed
error information when reader or card operations fail.
For an extended overview, see
SCard Class Overview.
Communicate directly with smart card readers and cards through PC/SC.
Chilkat.SCard is the low-level PC/SC smart card interface for
applications that need direct reader and card communication. It supports
reader discovery, reader connection, card status checking, APDU transmission,
reader-control commands, status-change monitoring, transactions, and
diagnostic access to underlying PC/SC errors. Use this class when the
application needs APDU-level control rather than a higher-level certificate,
minidriver, or PKCS#11 abstraction.
Reader discovery
Connect to cards
Transmit APDUs
Reader-control commands
Status monitoring
Transactions and diagnostics
Chilkat.SCard for direct PC/SC
reader and APDU-level work; use Chilkat.ScMinidriver for
card-minidriver certificate and key-container operations, and
Chilkat.Pkcs11 for PKCS#11 token or HSM sessions.
Object Creation
loSCard = CreateObject('Chilkat.SCard')Visual FoxPro is a 32-bit application and therefore uses the 32-bit Chilkat ActiveX. To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as CreateObject('Chilkat.SCard.11') for Chilkat v11.*.*.
Properties
ActiveProtocol
The name of the active protocol if connected smart card reader, or an empty string if not connected. Possible values are T0, T1, raw, undefined, or if not connected to a reader.
CardAtr
This is the Current ATR of a card in the connected reader.
topConnectedReader
The name of the currently connected smart card reader, or an empty string if not connected.
topContext
Contains the string user or system if this object has established a context (by calling EstablishContext). Contains the empty string if no context is established.
DebugLogFilePath
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
LastBinaryResult
This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.
LastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
LastStringResult
In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
topPcscLibPath
For Linux systems only. Specifies the full path of the libpcsclite.so shared lib. This property should only be used if the libpcsclite.so is in a non-standard location or if Chilkat cannot automatically located it.
topReaderStatus
The current status of the connected reader. Possible values are:
absent- There is no card in the reader.present- There is a card in the reader, but it has not been moved into position for use.swallowed- There is a card in the reader in position for use. The card is not powered.powered- Power is being provided to the card, but the reader driver is unaware of the mode of the card.negotiable- The card has been reset and is awaiting PTS negotiation.specific- The card has been reset and specific communication protocols have been established.
ScardError
The last error returned by an underlying PC/SC function. Can be one of the following:
SCARD_W_REMOVED_CARD- The smart card has been removed, so that further communication is not possible.SCARD_W_RESET_CARD- The smart card has been reset, so any shared state information is invalid.
...
VerboseLogging
If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
Methods
BeginTransaction
Establishes a temporary exclusive access mode for doing a series of commands in a transaction.
Returns 1 for success, 0 for failure.
topCheckStatus
Check the current status of the currently connected reader. Calling this method updates the ReaderStatus, ActiveProtocol, and CardAtr properties. If this method returns 0, none of the properties are updated.
Returns 1 for success, 0 for failure.
Connect
Establish a connection to a reader. The reader is the name of a reader returned from ListReaders. The shareMode can be shared, exclusive, or direct. The preferredProtocol can be 0 (valid only if the shareMode = direct), T0, T1, raw, or no_preference. (No preference is effectively T0 or T1.)
If successful, the state of this object instance is that it's connected to the reader.
Returns 1 for success, 0 for failure.
Disconnect
Terminates a connection with a reader. The disposition can be one of the following values:
leave: Do nothing.reset: Reset the card (warm reset).unpower: Power down the card (cold reset).eject: Eject the card.
Returns 1 for success, 0 for failure.
EndTransaction
Ends a previously begun transaction. The disposition is the action to be taken on the reader, and can be leave which is to do nothing, reset, unpower, or eject.
Returns 1 for success, 0 for failure.
topEstablishContext
Creates an Application Context to the PC/SC Resource Manager. This must be the first WinSCard function called in a PC/SC application. The scope can be user or system. After calling, this object will have context and all other methods will use the established context. The Context property will hold the value user or system if context was established, or will be empty if no context was established.
Returns 1 for success, 0 for failure.
topFindSmartcards
Returns JSON containing information about the smartcards currently inserted into readers.
Returns 1 for success, 0 for failure.
GetAttrib
Get an attribute from the IFD Handler (reader driver).
The attr can be one of the following:
ASYNC_PROTOCOL_TYPESATR_STRINGCHANNEL_IDCHARACTERISTICSCURRENT_BWTCURRENT_CLKCURRENT_CWTCURRENT_DCURRENT_EBC_ENCODINGCURRENT_FCURRENT_IFSCCURRENT_IFSDCURRENT_IO_STATECURRENT_NCURRENT_PROTOCOL_TYPECURRENT_WDEFAULT_CLKDEFAULT_DATA_RATEDEVICE_FRIENDLY_NAMEDEVICE_IN_USEDEVICE_SYSTEM_NAMEDEVICE_UNITESC_AUTHREQUESTESC_CANCELESC_RESETEXTENDED_BWTICC_INTERFACE_STATUSICC_PRESENCEICC_TYPE_PER_ATRMAX_CLKMAX_DATA_RATEMAX_IFSDMAXINPUTPOWER_MGMT_SUPPORTSUPRESS_T1_IFS_REQUESTSYNC_PROTOCOL_TYPESUSER_AUTH_INPUT_DEVICEUSER_TO_CARD_AUTH_DEVICEVENDOR_IFD_SERIAL_NOVENDOR_IFD_TYPEVENDOR_IFD_VERSIONVENDOR_NAME
The attribute data is returned in bd.
Returns 1 for success, 0 for failure.
topGetAttribStr
Get a string typed attribute from the IFD Handler (reader driver).
The attr can be one of the following, but should be limited to the particular attributes that return string values.
ASYNC_PROTOCOL_TYPESATR_STRINGCHANNEL_IDCHARACTERISTICSCURRENT_BWTCURRENT_CLKCURRENT_CWTCURRENT_DCURRENT_EBC_ENCODINGCURRENT_FCURRENT_IFSCCURRENT_IFSDCURRENT_IO_STATECURRENT_NCURRENT_PROTOCOL_TYPECURRENT_WDEFAULT_CLKDEFAULT_DATA_RATEDEVICE_FRIENDLY_NAMEDEVICE_IN_USEDEVICE_SYSTEM_NAMEDEVICE_UNITESC_AUTHREQUESTESC_CANCELESC_RESETEXTENDED_BWTICC_INTERFACE_STATUSICC_PRESENCEICC_TYPE_PER_ATRMAX_CLKMAX_DATA_RATEMAX_IFSDMAXINPUTPOWER_MGMT_SUPPORTSUPRESS_T1_IFS_REQUESTSYNC_PROTOCOL_TYPESUSER_AUTH_INPUT_DEVICEUSER_TO_CARD_AUTH_DEVICEVENDOR_IFD_SERIAL_NOVENDOR_IFD_TYPEVENDOR_IFD_VERSIONVENDOR_NAME
Returns .NULL. on failure
GetAttribUint
Get an unsigned integer typed attribute from the IFD Handler (reader driver).
The attr can be one of the following, but should be limited to the particular attributes that return unsigned integer values.
ASYNC_PROTOCOL_TYPESATR_STRINGCHANNEL_IDCHARACTERISTICSCURRENT_BWTCURRENT_CLKCURRENT_CWTCURRENT_DCURRENT_EBC_ENCODINGCURRENT_FCURRENT_IFSCCURRENT_IFSDCURRENT_IO_STATECURRENT_NCURRENT_PROTOCOL_TYPECURRENT_WDEFAULT_CLKDEFAULT_DATA_RATEDEVICE_FRIENDLY_NAMEDEVICE_IN_USEDEVICE_SYSTEM_NAMEDEVICE_UNITESC_AUTHREQUESTESC_CANCELESC_RESETEXTENDED_BWTICC_INTERFACE_STATUSICC_PRESENCEICC_TYPE_PER_ATRMAX_CLKMAX_DATA_RATEMAX_IFSDMAXINPUTPOWER_MGMT_SUPPORTSUPRESS_T1_IFS_REQUESTSYNC_PROTOCOL_TYPESUSER_AUTH_INPUT_DEVICEUSER_TO_CARD_AUTH_DEVICEVENDOR_IFD_SERIAL_NOVENDOR_IFD_TYPEVENDOR_IFD_VERSIONVENDOR_NAME
Returns 0xFFFFFFFF on failure.
topGetStatusChange
Blocks execution until the current availability of the cards in a specific set of readers changes.
This function receives a list of reader names in stReaderNames. It then blocks waiting for a change in state to occur for a maximum blocking time of maxWaitMs (in milliseconds) or forever if 0 is used.
Information about the current reader states and which reader(s) changed is returned in json. See the example below for more information.
To wait for a reader event (reader added or removed) you may use the special reader name \\?PnP?\Notification.
To cancel the ongoing call, call Cancel().
The stReaderNames contains the reader names to check. The json is empty on input, and if the call returns success contains information about the state (after the event change) of each reader.
Returns 1 for success, 0 for failure.
GetStatusChangeAsync (1)
Creates an asynchronous task to call the GetStatusChange method with the arguments provided.
Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.
Returns .NULL. on failure
GetStatusChangeCancel
Cancels an ongoing GetStatusChange method call. This would be called from a separate thread in your application if GetStatusChange was called synchronously.
Returns 1 for success, 0 for failure.
topListReaderGroups
Returns a list of currently available reader groups on the system. The reader groups are returned in readerGroups.
Returns 1 for success, 0 for failure.
topListReaders
Returns a list of currently available readers on the system.
Returns 1 for success, 0 for failure.
Reconnect
Reestablishes a connection to a reader that was previously connected to using Connect().
In a multi application environment it is possible for an application to reset the card in shared mode. When this occurs any other application trying to access certain commands will be returned the value SCARD_W_RESET_CARD. When this occurs Reconnect() must be called in order to acknowledge that the card was reset and allow it to change its state accordingly.
The shareMode can be shared, exclusive, or direct. The preferredProtocol can be 0 (valid only if the shareMode = direct), T0, T1, raw, or no_preference. (No preference is effectively T0 or T1.) The action is the desired action taken on the card/reader. It can be leave, reset, unpower, or eject.
If successful, the state of this object instance is that it's connected to the reader.
Returns 1 for success, 0 for failure.
topReleaseContext
Destroys a communication context to the PC/SC Resource Manager. This must be the last function called in a PC/SC application.
Returns 1 for success, 0 for failure.
topSendControl
Sends a command directly to the IFD Handler (reader driver) to be processed by the reader.
This is useful for creating client side reader drivers for functions like PIN pads, biometrics, or other extensions to the normal smart card reader that are not normally handled by PC/SC.
The command data is sent in bdSend. The response is written to bdRecv.
Returns 1 for success, 0 for failure.
topSendControlHex
Sends a command directly to the IFD Handler (reader driver) to be processed by the reader.
This is useful for creating client side reader drivers for functions like PIN pads, biometrics, or other extensions to the normal smart card reader that are not normally handled by PC/SC.
The command data is provided as a hex string in sendData. The response is written to bdRecv.
Returns 1 for success, 0 for failure.
topTransmit
Sends an APDU to the smart card contained in the currently connected reader. The protocol can be T0, T1, or raw. The APDU to be sent is contained in bdSend. The response from the card is contained in bdRecv. The maxRecvLen is the maximum response size (in bytes) willing to be accepted.
Returns 1 for success, 0 for failure.
topTransmitHex
Sends an APDU to the smart card contained in the currently connected reader. The protocol can be T0, T1, or raw. The APDU (in hexadecimal) to be sent is passed in apduHex. The response from the card is contained in bdRecv. The maxRecvLen is the maximum response size (in bytes) willing to be accepted.
Returns 1 for success, 0 for failure.
topEvents
A Visual FoxPro application receives Chilkat ActiveX events by defining a class that IMPLEMENTS the _IChilkatEvents interface, creating an instance of it, and binding that instance to the Chilkat object with EVENTHANDLER(). Visual FoxPro requires the class to implement every method of the interface, so the class below includes a PROCEDURE for each event; leave the ones you do not need empty. The TextData and BinaryData events are defunct: they are deprecated and are never called, but their procedures must still exist because the interface declares them.
Important: Event callbacks from asynchronous method calls are generally not possible from the ActiveX. Events fire during synchronous method calls.
sCardEventHandler = CREATEOBJECT("MySCardEvents")
loSCard = CreateObject('Chilkat.SCard')
EVENTHANDLER(loSCard, sCardEventHandler)
DEFINE CLASS MySCardEvents AS SESSION OLEPUBLIC
IMPLEMENTS _IChilkatEvents IN "Chilkat.SCard"
PROCEDURE _IChilkatEvents_AbortCheck(abort As Number)
? "AbortCheck"
ENDPROC
* The BinaryData event is defunct: it is deprecated and is never called.
* The procedure must exist because the interface declares it, but it can be left empty.
PROCEDURE _IChilkatEvents_BinaryData(data As Variant)
ENDPROC
PROCEDURE _IChilkatEvents_PercentDone(pctDone As Number, abort As Number)
? "PercentDone"
ENDPROC
PROCEDURE _IChilkatEvents_ProgressInfo(name As String, value As String)
? "ProgressInfo"
ENDPROC
PROCEDURE _IChilkatEvents_TaskCompleted(task As Generic)
? "TaskCompleted"
ENDPROC
* The TextData event is defunct: it is deprecated and is never called.
* The procedure must exist because the interface declares it, but it can be left empty.
PROCEDURE _IChilkatEvents_TextData(data As String)
ENDPROC
ENDDEFINE
AbortCheck
Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.
FoxPro event implementation:
* Add to the MySCardEvents class shown in the Events overview above.
PROCEDURE _IChilkatEvents_AbortCheck(abort As Number)
* Set abort to 1 to abort the method in progress.
ENDPROC
PercentDone
This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).
The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.
To abort the operation, set the abort output argument to 1. This will cause the method to terminate and return a failure status or corresponding failure value.
FoxPro event implementation:
* Add to the MySCardEvents class shown in the Events overview above.
PROCEDURE _IChilkatEvents_PercentDone(pctDone As Number, abort As Number)
* pctDone ranges from 1 to 100. Set abort to 1 to abort the method in progress.
ENDPROC
ProgressInfo
This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.
Note: Some Chilkat methods don't fire any ProgressInfo events.
FoxPro event implementation:
* Add to the MySCardEvents class shown in the Events overview above.
PROCEDURE _IChilkatEvents_ProgressInfo(name As String, value As String)
? name + ": " + value
ENDPROC
TaskCompleted
Called from the background thread when an asynchronous task completes.
FoxPro event implementation:
* Add to the MySCardEvents class shown in the Events overview above.
PROCEDURE _IChilkatEvents_TaskCompleted(task As Generic)
* task is the Task object that has completed.
ENDPROC