Hello,
i've got a problem with pointers in the following function which i want
to use:
I16 __stdcall DO_ReadPort (U16 CardNumber, U16 Port, U32 *Value)
The function is supposed to read out the status of a digital port of
analog digital interface card.
I got this function from Dask.h which came with the card. The relevant
lines concerning this function are the following:
typedef short I16;
typedef unsigned short U16;
typedef unsigned long U32;
I16 __stdcall DO_ReadPort (U16 CardNumber, U16 Port, U32 *Value)
I tried to implement this function into python:
# I16 __stdcall DO_ReadPort (U16 CardNumber, U16 Port, U32 *Value);
ReadOPort = dask.DO_ReadPor t
ReadOPort.argty pes = [c_ushort, c_ushort, c_ulong]
ReadOPort.resty pe = c_short
I can't handle the pointer "Value" which should be an unsigned long
pointer. I'd be very happy, if u could give me a hint how to implement
this pointer into python.
Thanks a lot
Carlo and Pierre
3  5005 
Le 29 Aug 2005 06:19:17 -0700, ru**********@we b.de a écrit : Hello,
i've got a problem with pointers in the following function which i want
to use:
I16 __stdcall DO_ReadPort (U16 CardNumber, U16 Port, U32 *Value)
The function is supposed to read out the status of a digital port of
analog digital interface card.
I got this function from Dask.h which came with the card. The relevant
lines concerning this function are the following:
typedef short I16;
typedef unsigned short U16;
typedef unsigned long U32;
I16 __stdcall DO_ReadPort (U16 CardNumber, U16 Port, U32 *Value)
I tried to implement this function into python:
# I16 __stdcall DO_ReadPort (U16 CardNumber, U16 Port, U32 *Value);
ReadOPort = dask.DO_ReadPor t
ReadOPort.argty pes = [c_ushort, c_ushort, c_ulong]
ReadOPort.resty pe = c_short
I can't handle the pointer "Value" which should be an unsigned long
pointer. I'd be very happy, if u could give me a hint how to implement
this pointer into python.
You can use the ctypes.byref() function (as it is in an argulent list):
ReadOPort.argty pes = (c_ushort, c_ushort, ctypes.POINTER( c_ulong) )
ReadOPort.resty pe = c_short
status = c_ulong() # status value to be read
number = c_ushort(1) # CardNumber = 1
port = c_ushort(11)
rc = ReadOPort(numbe r, port, ctypes.byref(st atus))
print rc, ststus
Thanks a lot
Carlo and Pierre
thanks a bunch, i just got the answer myself. next time i think about
it a little longer.
thanks again
carlo
F. Petitjean wrote: Le 29 Aug 2005 06:19:17 -0700, ru**********@we b.de a écrit :
....
You can use the ctypes.byref() function (as it is in an argulent list):
ReadOPort.argty pes = (c_ushort, c_ushort, ctypes.POINTER( c_ulong) )
ReadOPort.resty pe = c_short
status = c_ulong() # status value to be read
number = c_ushort(1) # CardNumber = 1
port = c_ushort(11)
rc = ReadOPort(numbe r, port, ctypes.byref(st atus))
print rc, ststus
Just as an FYI, Thomas has recently added code which does the byref
automatically. The version of ctypes in CVS HEAD will allow you to pass
in a c_ulong where the argtype is ctypes.POINTER( c_ulong).
Have fun,
Mike
--
_______________ _______________ _______________ ___
Mike C. Fletcher
Designer, VR Plumber, Coder http://www.vrplumber.com http://blog.vrplumber.com This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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