[Cython] Fix integer width constant names in stdint.pxd

[Mansour Moufid]

On Mon, Jan 2, 2012 at 8:48 PM, Lisandro Dalcin <dalcinl at gmail.com> wrote:
> On 2 January 2012 22:37, Mansour Moufid <mansourmoufid at gmail.com> wrote:
>> Now my issue is as follows.
>>
>> (I CCed the cython-users list if this question is more appropriate there.)
>>
>> I have a simple file, int.pyx:
>>
>> from libc.stdint cimport *
>> print long(UINT8_MAX)
>> print long(UINT16_MAX)
>> print long(UINT32_MAX)
>> print long(UINT64_MAX)
>>
>> with the usual setup.py stuff. Compiling and running:
>>
>> $ python setup.py build_ext --inplace
>> ...
>> int.c:566:3: warning: overflow in implicit constant conversion [-Woverflow]
>> ...
>> $ python -c 'import int'
>> 255
>> 65535
>> -1
>> -1
>>
>> So obviously there are overflows here. Checking int.c, I see:
>>
>>  /* "int.pyx":2
>>  * from libc.stdint cimport *
>>  * print long(UINT8_MAX)             # <<<<<<<<<<<<<<
>>  * print long(UINT16_MAX)
>>  * print long(UINT32_MAX)
>>  */
>>  __pyx_t_1 = PyInt_FromLong(UINT8_MAX);
>>
>> and so on...
>>
>> PyInt_FromLong is used for all these constants, regardless of
>> signedness or width, so any argument larger than LONG_MAX overflows,
>> *before* being converted to the arbitrary-size Python integer type.
>>
>> I don't know if this is a bug, or if I'm overlooking something. Is
>> there a way for me to use these constants with Python's arbitrary-size
>> integers?
>>
>
> All these constants are declared as "enum", so Cython promotes them to
> "int". Once again, Cython should have something like a "const" type
> qualifier to poperly declare these compile-time constants.
>
> As workaround, you could explicitly cast the constants like this
> "print long(<uint8_t>UINT8_MAX)"

This works great. Exactly what I was looking for, thanks.

Mansour