int vs long

[Gabriel Genellina]

En Sun, 16 Dec 2007 20:28:02 -0300, Troels Thomsen <"nej  
tak..."@bag.python.org> escribi�:

>
> The readFile function from the win32 package aparently really expect an
> integer :
>
>     def inWaiting(self):
>         """Returns the number of bytes waiting to be read"""
>         flags, comstat = ClearCommError(self.__handle)
>         return comstat.cbInQue
>
> ReadFile(h, s.inWaiting())
>
> My code crashes because inWaiting returns a long, not an int

That's very strange. The cbInQue field is a DWORD in C, seen as an int in  
Python. How do you know it returns a long?

> Why is that different on my machine and my collegues ? Have I or he
> installed a wrong version of a package?
> CPython 2.5.

And pywin32 build 210, I presume.

> Was not expecting int<->long type problems in excactly python language.
> Is that because we are navigating so close to the win32 api that the  
> types
> are more strictly enforced ?

Somewhat. At the API level, function arguments have to be converted to  
native C types, like ReadFile expecting a DWORD. Any number greater than  
2**32 won't fit, but I can't think how such thing could happen looking at  
those few posted code lines.

-- 
Gabriel Genellina