I'm trying to use PyArray_FROM_OF from Cython and the generated C code keeps crashing. Dag said on the Cython list that he wasn't sure what was going on, so maybe someone here will have an idea. The line that gdb says is crashing is: #0 0x00e48287 in __pyx_pf_3_vq_vq (__pyx_self=0x0, __pyx_args=0xca2d8, __pyx_kwds=0x0) at _vq_rewrite.c:1025 1025 __pyx_t_1 = PyArray_FROM_OF(((PyObject *)__pyx_v_obs), __pyx_v_flags); if (unlikely(!__pyx_t_1)) {__pyx_filename = __pyx_f[0]; __pyx_lineno = 90; __pyx_clineno = __LINE__; goto __pyx_L1_error;} obs and obs_a are both cdef'd np.ndarrays, and the former (obs) is passed in as an argument. I define flags as cdef int flags = np.NPY_CONTIGUOUS | np.NPY_ALIGNED | np.NPY_NOTSWAPPED and then the line that crashes is obs_a = np.PyArray_FROM_OF(obs, flags) Does anyone know what I'm doing wrong? (I know I could use np.ascontiguous, but as far as I can tell this _should_ work) David