ValueError: Procedure probably called with not enough arguments (8 bytes missing)

LabJack Support labjacksupport at
Sat Aug 8 00:16:57 CEST 2009

Hello! I am chasing around a problem that I am having with ctypes and
I am hoping someone can help out. Here is the Python code:

    def asynch(self, baudrate, data, idNum=None, demo=0, portB=0,
enableTE=0, enableTO=0, enableDel=0, numWrite=0, numRead=0):
        Name: U12.asynchConfig(fullA, fullB, fullC, halfA, halfB,
halfC, idNum=None, demo=None, timeoutMult=1, configA=0, configB=0,
        Args: See section 4.12 of the User's Guide
        Desc: Requires firmware V1.1 or higher. This function writes
to the asynch registers and sets the direction of the D lines (input/
output) as needed.

        >>> dev = U12()
        >>> dev.asynchConfig(96,1,1,22,2,1)
        >>> {'idNum': 1}

        #Check id number
        if idNum is None:
            idNum =
        idNum = ctypes.c_long(idNum)

        # Check size of data
        if len(data) > 18: raise ValueError("data can not be larger
than 18 elements")

        # Make data 18 elements large
        dataArray = [0] * 18
        for i in range(0, len(data)):
            dataArray[i] = data[i]
        print dataArray
        dataArray = listToCArray(dataArray, ctypes.c_long)

        ecode = staticLib.AsynchConfig(ctypes.byref(idNum), demo,
portB, enableTE, enableTO, enableDel, baudrate, numWrite, numRead,

        if ecode != 0:print ecode # TODO: Switch this out for

        return {"idnum":long, "data":dataArray}

Here is the method signature of the c function:

long Asynch(	long *idnum,
				long demo,
				long portB,
				long enableTE,
				long enableTO,
				long enableDel,
				long baudrate,
				long numWrite,
				long numRead,
				long *data)

Thank you in advance,

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