[Pyrex] Segfault when trying to set attribute of another class

[Greg Ewing]

Armin Bauer <armin.bauer at desscon.com>:

> cdef class CLASS2:
> 	cdef STRUCT2 *_struct2
> 	
> 	def get_class1(self):
> 		s = CLASS1()
> 		s._set_struct1(<object>get_struct1_from_struct2(self._struct2))
> 		print "test2"
> 		return s

It looks like you're trying to smuggle a non-Python pointer into the
_set_struct1 method by pretending it's a Python object. That won't
work.

You should NEVER cast a pointer to a Python type unless it really and
truly points to a Python object. Crashing and burning is guaranteed to
result.

There are two things you could do here:

(1) Assign the pointer directly, not bothering with a _set_struct1
    method.

  cdef class CLASS2:
    ...
    def get_class1(self):
      cdef CLASS1 *s       # <--- note type declaration
      s = CLASS1()
      s._struct1 = get_struct1_from_struct2(self._struct2)
      ...

(2) If you particularly want to set it via an accessor method, use
    a C method (introduced in Pyrex 0.9):

  cdef class CLASS1:
    ...
    # --- Note the following header ---
    cdef void _set_struct1(self, STRUCT1 *s1):
      self._struct1 = s1

  cdef class CLASS2:
    ...
    def get_class1(self):
      cdef CLASS1 *s       # <--- note type declaration
      s = CLASS1()
      s._set_struct1(get_struct1_from_struct2(self._struct2))
      ...

Greg Ewing, Computer Science Dept, +--------------------------------------+
University of Canterbury,	   | A citizen of NewZealandCorp, a	  |
Christchurch, New Zealand	   | wholly-owned subsidiary of USA Inc.  |
greg at cosc.canterbury.ac.nz	   +--------------------------------------+