Hello. At first excuse me for my poor English. I've making a python library for handle the pcican board, using the canlib library. It works fine. Now, I have to integrate to a twisted application that I made, for package encapsulation over tcp/ip. This works fine in serialport using abstract.filedescriptor and pyserial, but in the canlib case I have no file descriptor for this. What can I do for encapsulate like serial protocol, but with canlib methods? I have to re factorize the pycanlib library to build a file descriptor that represents, or is a way to readapt the abstract.filedescriptor for that? The methods that I have is: Channel.readWait() <- this is persistent Channel.read() <-this is not persistent. If buffer is empty returns. Channel.write(<can package attributes>) More details: This is the file descriptor I wrote... ---------------- # twisted imports from twisted.internet import abstract, fdesc, main import canlib from canlib import canOPEN_EXCLUSIVE, canWANT_EXTENDED, BAUD_1M, canDRIVER_NORMAL class CANConnector(abstract.FileDescriptor): """ Conector para el dispositivo pcican usando pycanlib """ connected = 1 def __init__(self, protocol, conf, reactor): abstract.FileDescriptor.__init__(self, reactor) self._channel = canlib.Channel(0) self._channel.open(canOPEN_EXCLUSIVE | canWANT_EXTENDED) self._channel.setBusOff() self._channel.setBusParams(BAUD_1M, 4, 3, 1, 1) self._channel.setBusOutputControl(canDRIVER_NORMAL) self._channel.setBusOn() self.reactor = reactor self.protocol = protocol self.protocol.makeConnection(self) self.startReading() def writeSomeData(self, data): return self._channel.write(1000, data, 10, 0) def doRead(self): pack = self._channel.readWait() # returns the message of package return pack['msg'] def connectionLost(self, reason=None): abstract.FileDescriptor.connectionLost(self, reason) self._channel.close() ------------ in the main tac service this is how I use the connector: --------------- (...) class ServiceChannel(protocol.Protocol): def connectionMade(self): print 'Canal conectado' def dataReceived(self, data): print "datorecibido" s.writeOnPort(data) def connectionLost(self): print 'Canal desconectado' class SimulatorService(service.Service): (...) def startChannel(self): (...) c = ServiceChannel() (...) self.channel = CANConnector(c, self.conf.channel, reactor) (...) def writeOnPort(self, data): self.factory.instance.transport.write(data) -------- This application pipes the can comunications whith a tcp ip port. Then ,when I run: $ twistd -ny main.tac 2007/11/30 10:52 -0300 [-] Log opened. 2007/11/30 10:52 -0300 [-] twistd 2.5.0 (/usr/bin/python 2.5.1) starting up 2007/11/30 10:52 -0300 [-] reactor class: <class ' twisted.internet.selectreactor.SelectReactor'> 2007/11/30 10:52 -0300 [-] Loading main.tac... 2007/11/30 10:52 -0300 [-] /usr/bin/twistd: option -n not recognized 2007/11/30 10:52 -0300 [-] /usr/bin/twistd: Try --help for usage details. 2007/11/30 10:52 -0300 [-] Loaded. 2007/11/30 10:52 -0300 [-] __builtin__.ServiceFactory starting on 5000 2007/11/30 10:52 -0300 [-] Starting factory <__builtin__.ServiceFactory instance at 0x84069cc> 2007/11/30 10:52 -0300 [__builtin__.ServiceFactory] {'protocol': 'can', 'number': '0', 'channel': '1'} 2007/11/30 10:52 -0300 [__builtin__.ServiceFactory] Canal conectado 2007/11/30 10:52 -0300 [__builtin__.ServiceFactory] channel started................. 2007/11/30 10:52 -0300 [__builtin__.ServiceFactory] se generan los archivos de registro <... (Connect to 5000 port ) ..> 2007/11/30 10:52 -0300 [__builtin__.ServiceFactory] Conexion establecida desde IPv4Address(TCP, '192.168.6.38', 5000) 2007/11/30 10:52 -0300 [-] Unhandled Error Traceback (most recent call last): File "/usr/lib/python2.5/site-packages/twisted/scripts/_twistd_unix.py", line 214, in postApplication app.runReactorWithLogging(self.config, self.oldstdout, self.oldstderr) File "/usr/lib/python2.5/site-packages/twisted/application/app.py", line 113, in runReactorWithLogging reactor.run() File "/usr/lib/python2.5/site-packages/twisted/internet/posixbase.py", line 220, in run self.mainLoop() File "/usr/lib/python2.5/site-packages/twisted/internet/posixbase.py", line 231, in mainLoop self.doIteration(t) --- <exception caught here> --- File "/usr/lib/python2.5/site-packages/twisted/internet/selectreactor.py", line 97, in doSelect [], timeout) exceptions.ValueError: file descriptor cannot be a negative integer (-1) 2007/11/30 10:52 -0300 [-] Malformed file descriptor found. Preening lists. 2007/11/30 10:52 -0300 [-] bad descriptor <can.CANConnector object at 0x83e94ec> Thanks for your attention. Fran PD: If anybody is interested in this pycanlib library I pass the source for liberation. -- "El hombre se descubre cuando se mide con un obstáculo" (Saint Exupéry)