memoryview(ctypes.Structure) does not produce the correct format string

Issue #2930 resolved
created an issue

The following passes on CPython, fails on PyPy (mv.format is B)

class Struct(Structure):
    _fields_ = [('a', c_int16)]

Struct3 = 3 * Struct

c_array = (2 * Struct3)(
    Struct3(Struct(a=1), Struct(a=2), Struct(a=3)),
    Struct3(Struct(a=4), Struct(a=5), Struct(a=6))

mv = memoryview(c_array)
assert mv.format == 'T{<h:a:}'

The memoryview call goes to _CData.__buffer__ in, which should not just call buffer(self._buffer)

Comments (5)

  1. mattip reporter

    In python3 there is memoyobject.cast. We should add it to python2 memoryview (W_MemoryView.descr_cast), and use it from app-level to fixup mv

  2. mattip reporter

    Change the plan since cpython3 does not support casting to complex format. So instead we will have a __pypy__.newmemoryview(buffer, format, *, shape, strides) approximately - a mix of the constructor API and cast API

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