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POCython and C++ inheritance
primarykey
Id
10298371
data
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10525605
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3
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2012-04-24T13:00:28.463
FavoriteCount
5
LastActivityDate
2018-02-13T08:25:00.607
LastEditDate
2012-05-09T15:58:40.413
LastEditorUserId
49886
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49886
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0
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1
Score
11
ViewCount
3687
LastEditorDisplayName
text
Body
I have 2 classes, A and B. B inherits from A. <pre class="lang-cpp prettyprint-override"><code>//C++ class A { public: int getA() {return this->a;}; A() {this->a = 42;} private: int a; }; class B: public A { public: B() {this->b = 111;}; int getB() {return this->b;}; private: int b; }; </code></pre> Now I would like to interface those two classes using Cython and have the possibility to call the getA() method from a B instance: <pre class="lang-python prettyprint-override"><code>a = PyA() b = PyB() assert a.getA() == b.getA() </code></pre> Currently my pyx file looks like this: <pre class="lang-cython prettyprint-override"><code>cdef extern from "Inherit.h" : cdef cppclass A: int getA() cdef cppclass B(A): int getB() cdef class PyA: cdef A* thisptr def __cinit__(self): print "in A: allocating thisptr" self.thisptr = new A() def __dealloc__(self): if self.thisptr: print "in A: deallocating thisptr" del self.thisptr def getA(self): return self.thisptr.getA() cdef class PyB(PyA): def __cinit__(self): if self.thisptr: print "in B: deallocating old A" del self.thisptr print "in B: creating new b" self.thisptr = new B() def __dealloc__(self): if self.thisptr: print "in B: deallocating thisptr" del self.thisptr self.thisptr = <A*>0 def getB(self): return (<B*>self.thisptr).getB() </code></pre> While I hope this code is not doing anything too dangerous, I also hope there is a better way to handle it. Also using the module generates the following output: <pre class="lang-python prettyprint-override"><code>>>> from inherit import * >>> b = PyB() in A: allocating thisptr in B: deallocating old A in B: creating new b >>> b.getA() 42 >>> b.getB() 111 >>> del b in B: deallocating thisptr </code></pre> And I don't really like allocating an A instance just to free it immediately after. Any advice about how to do it correctly ?
Tags
<c++><python><inheritance><cython>
Title
Cython and C++ inheritance
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