On 2 January 2012 22:37, Mansour Moufid <mansourmou...@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)" -- Lisandro Dalcin --------------- CIMEC (INTEC/CONICET-UNL) Predio CONICET-Santa Fe Colectora RN 168 Km 472, Paraje El Pozo 3000 Santa Fe, Argentina Tel: +54-342-4511594 (ext 1011) Tel/Fax: +54-342-4511169 _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
