Re: [ctypes-users] calling ' extern "C" int __declspec(dllexport) ' declared functions?

[Mark M. <mar...@au...>]

Hi Ray,

> -----Original Message-----
> From: RayS [mailto:ra...@bl...] 
> Sent: Friday, August 13, 2010 12:24 PM
> To: Mark McMahon; cty...@li...
> Subject: RE: [ctypes-users] calling ' extern "C" int __declspec(dllexport) ' declared functions?
> 
> At 06:51 PM 8/12/2010, Mark McMahon wrote:
> ># can you get a reference the DLL
> >dll = ctypes.windll.YOURDLLNAME
> 
> yes, it also wasn't immediately obvious that it was a cdecl (which I 
> used with partial sucess), not a windll
> 
yes - cdl or windll - if one works - use it:)


> >Can you get references to the functions...
> >SetBlockSize = dll.SetBlockSize  #using SetBlockSize is easier as 
> >the argument is a plain int
> >
> >ret = SetBlockSize = SetBlockSize(123)
> 
> it returns zero (apparently OK, by the .h file comment)

So you can see the function, and you can evey call some of them :)

> 
> ># does ret have the return code for success (or expected return value?)
> >
> >For GetBlockSize - you will need to read the doc and see what to do 
> >with pointer/reference values :)  (but usually ctypes.byref(var) or 
> >ctypes.pointer(var) are what you need).
> 
> I tried both byref and pointer, but both returned -1; I'll be talking 
> to the hardware maker tomorrow

are you doing something like the following
val =  ctypes.c_int()
dll.GetBlockSize(ctypes.byref(val))

or
dll.GetBlockSize(ctypes.pointer(val))

Because the value will be modified - you need to create it separately first

> 
> Do you write Python code for AutoCAD?

I don't work on AutoCAD - but I use Python for automation tasks.
> 
> Thanks,
> Ray 

Hope that helps,
  Mark
>