[ctypes-users] Re: help: Procedure called with not enough arguments (16 bytes missing) or wrong cal

[Thomas H. <th...@py...>]

Guillaume Proux <gui...@sc...> writes:

> Hi,
>
>>>>> pg = cdll.LoadLibrary("c:\PrintPRO3.dll")
>>>>> pg
>>>>
>> <CDLL 'c:\PrintPRO3.dll', handle 1800000 at 12f7e90>
>> Traceback (most recent call last):
>>  File "<interactive input>", line 1, in ?
>> ValueError: Procedure called with not enough arguments (16 bytes
>> missing) or wrong calling convention
>
> Probably the right answer is "wrong calling convention"
> try
> pg = windll.LoadLibrary("c:\PrintPRO3.dll")

I wonder if ctypes should change its behaviour here.  First, when this
error occurrs, the functions has successfully been called.  If ctypes
would emit a warning instead of raising an error, one could even get the
return value.

Second, ctypes *is* able to restore the stack after the call, even when
the wrong calling convention had been used - it can already detect this.

So, maybe even the warning should be supressed? That was how the old
calldll did it, IIRC.

The 'problem' would be that the differences between cdll/CDLL and
windll/WinDLL would vanish.

And the above is only true for calling functions in libraries -
implementing callback functions with WINFUNCTYPE and CFUNCTYPE would
have to use the correct calling convention (but maybe this is expert
stuff anyway ;).

Opinions?

Thomas