int vs long

[Troels Thomsen]

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

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

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 ?

Thx in advance
Troels

[Gabriel Genellina]

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

>
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

[Nick Craig-Wood]

Gabriel Genellina <ga*******@yahoo.com.arwrote:

En Sun, 16 Dec 2007 20:28:02 -0300, Troels Thomsen <"nej
tak..."@bag.python.orgescribi?:

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.

Actually any number >= 2**31 won't fit in a python int.

>>2**31

2147483648L

According to my headers DWORD is defined like this

typedef unsigned long DWORD;

So you might see longs returned when you expected ints if the result
was >= 0x8000000.

--
Nick Craig-Wood <ni**@craig-wood.com-- http://www.craig-wood.com/nick

[Gabriel Genellina]

En Mon, 17 Dec 2007 10:30:05 -0300, Nick Craig-Wood <ni**@craig-wood.com>
escribió:

Gabriel Genellina <ga*******@yahoo.com.arwrote:

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

>
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.

Actually any number >= 2**31 won't fit in a python int.

>>2**31

2147483648L

According to my headers DWORD is defined like this

typedef unsigned long DWORD;

So you might see longs returned when you expected ints if the result
was >= 0x8000000.

More than 2GB waiting to be read from a serial port? If that were the case
the OP has a very big throughput problem rather than an API mismatch :)

--
Gabriel Genellina

[Hendrik van Rooyen]

"Nick Craig-Wood" <nic...od.comwrote:

So you might see longs returned when you expected ints if the result
was >= 0x8000000.

did you mean 0x80000000 ?

;-)

- Hendrik

[Nick Craig-Wood]

Hendrik van Rooyen <ma**@microcorp.co.zawrote:

"Nick Craig-Wood" <nic...od.comwrote:

So you might see longs returned when you expected ints if the result
was >= 0x8000000.

did you mean 0x80000000 ?

;-)

Yes - well spotted!
--
Nick Craig-Wood <ni**@craig-wood.com-- http://www.craig-wood.com/nick