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Author image Wolfgang Hommel


Chipcard::PCSC - Smart card reader interface library


 my $hContext = new Chipcard::PCSC();

 @ReadersList = $hContext->ListReaders ();

 $hContext->GetStatusChange(\@readers_states, $timeout);

 $apdu = Chipcard::PCSC::array_to_ascii(@apdu);

 @apdu = Chipcard::PCSC::ascii_to_array($apdu);

 $hContext = undef;


The PCSC module implements the Chipcard::PCSC class. Objects of this class are used to communicate with the PCSC-lite daemon (see pcscd(1) for more information).

PC/SC represents an abstraction layer to smart card readers. It provides a communication layer with a wide variety of smart card readers through a standardized API.

A PCSC object can be used to communicate with more than one reader through Chipcard::PCSC::Card objects. Please read Chipcard::PCSC::Card for extended information on how to talk to a smart card reader.

A PCSC object uses the following property: $pcsc_object->{hContext} the context returned by the pcsc library


The following methods can be used to construct a PCSC object:

  • $hContext = new Chipcard::PCSC($scope, $remote_host);

    • $scope is the scope of the connection to the PC/SC daemon. It can be any of the following:

       $Chipcard::PCSC::SCARD_SCOPE_USER     (not used by PCSClite);
       $Chipcard::PCSC::SCARD_SCOPE_TERMINAL (not used by PCSClite);
       $Chipcard::PCSC::SCARD_SCOPE_SYSTEM   Services on the local machine;
       $Chipcard::PCSC::SCARD_SCOPE_GLOBAL   Services on a remote host.
    • $remote_host is the host name of the remote machine to contact. It is only used when $scope is equal to $Chipcard::PCSC::SCARD_SCOPE_GLOBAL. A null value means localhost.

  • $hContext = new Chipcard::PCSC($scope);

    This method is equivalent to:

     $hContext = new Chipcard::PCSC($scope, 0);
  • $hContext = new Chipcard::PCSC();

    This method is equivalent to:

     $hContext = new Chipcard::PCSC($Chipcard::PCSC::SCARD_SCOPE_SYSTEM, 0);


Chipcard::PCSC constructors return an undef value when the object can not be created. $Chipcard::PCSC::errno can be used to get more information about the error. (See section "ERROR HANDLING" below for more information)


Here is a list of all the methods that can be used with a PCSC object.

  • hContext->ListReaders( $group );

    This method returns the available readers in the given $group. If omitted, $group defaults to a null value meaning "all groups". Please note that as of this writing, $group can safely be omitted as it is not used by PCSClite.

    The return value upon successful completion is an array of strings: one string by available reader. If an error occurred, the undef value is returned and $Chipcard::PCSC::errno should be used to get more information about the error. (See section "ERROR HANDLING" below for more information). The following example describes the use of ListReaders:

     $hContext = new Chipcard::PCSC();
     die ("Can't create the PCSC object: $Chipcard::PCSC::errno\n")
            unless (defined $hContext);
     @ReadersList = $hContext->ListReaders ();
     die ("Can't get readers' list: $Chipcard::PCSC::errno\n")
            unless (defined($ReadersList[0]));
     $, = "\n  ";
     print @ReadersList . "\n";
  • $hContext->GetStatusChange(\@readers_states, $timeout);

    The method $hContext->GetStatusChange(\@readers_states, $timeout) uses a reference to a list of hashes.

     # create the list or readers to watch
     map { push @readers_states, ({'reader_name'=>"$_"}) } @ReadersList;
     @StatusResult = $hContext->GetStatusChange(\@readers_states);

    The keys of the hash are: 'reader_name', 'current_state', 'event_state' and 'ATR'.

    To detect a status change you have to first get the status and then copy the 'event_state' in the 'current_state'. The method will return when both states are different or a timeout occurs.

     @StatusResult = $hContext->GetStatusChange(\@readers_states);
     foreach $reader (@readers_states)
       $reader->{current_state} = $reader->{event_state};
     @StatusResult = $hContext->GetStatusChange(\@readers_states);
  • $hContext->GetStatusChange(\@readers_states);

    This method is equivalent to:

     $hContext->GetStatusChange(\@readers_states, 0xFFFFFFFF);

    The timeout is set to infinite.

  • $apdu_ref = Chipcard::PCSC::ascii_to_array($apdu);

    The method Chipcard::PCSC::Card::Transmit() uses references to arrays as in and out parameters. The Chipcard::PCSC::ascii_to_array() is used to transform an APDU in ASCII format to a reference to an array in the good format.


     $SendData = Chipcard::PCSC::ascii_to_array("00 A4 01 00 02 01 00");
  • $apdu = Chipcard::PCSC::array_to_ascii($apdu_ref);

    This method is used to convert the result of a Chipcard::PCSC::Card::Transmit() into ASCII format.


     $RecvData = $hCard->Transmit($SendData);
     print Chipcard::PCSC::array_to_ascii($RecvData);


All functions from PCSC objects save the return value in a global variable called $Chipcard::PCSC::errno. This variable therefore holds the latest status of PCSC.

It is a double-typed magical variable that behaves just like $!. This means that it both holds a numerical value describing the error and the corresponding string. The numerical value may change from a system to another as it depends on the PCSC library...

Here is a small example of how to use it:

 $hContext = new Chipcard::PCSC();
 die ("Can't create the PCSC object: $Chipcard::PCSC::errno\n")
     unless (defined $hContext);

In case the last call was successful, $Chipcard::PCSC::errno contains the SCARD_S_SUCCESS status. Here is a list of all possible error codes. They are defined as read-only variables with in the PCSC module:



PCSClite users will also be able to use the following (PCSClite specific) codes:


In addition, the wrapper defines:



pcscd(1) manpage has useful information about PC/SC lite. Chipcard::PCSC::Card manpage gives information about how to communicate with a reader and the smart card inside it.


(C) Lionel VICTOR & Ludovic ROUSSEAU, 2001-2004, GNU GPL (C) Ludovic ROUSSEAU, 2005-2008, GNU GPL


 Lionel VICTOR <lionel.victor@unforgettable.com>

 Ludovic ROUSSEAU <ludovic.rousseau@free.fr>