Python bindings on Windows crash

[Rene van Paassen]

I am preparing windows/linux/osx packages of PyODE 0.16 for my students (and others) to use, they are currently a pull request in the staged-recipes for conda-forge here

In doing this, I found that the Windows version of an ode-using program would fail without warning, causing an immediate exit of the program.

From the compiler warnings on the Python binding, I found that the problem was that the Windows “long” int, (32 bit), cannot hold a pointer on Win64; this is used in ode.pxd and ode.pyd files. I replaced the appropriate longs by “long long”.

I created attached patch, currently in use for my conda recipe, which fixes the problem. I currently only apply the patch to the Windows build, but expect that it will seamlessly work on Linux and OSX as well.

[Edgar 't Hart]

Normally you would use a DWORD* or a DWORD_PTR, this way the size is 64bit wide in a x64 process and 32bit wide in a x86 process

[Rene van Paassen]

Those certainly won’t work on Linux or OSX….

uintptr_t ?

https://stackoverflow.com/questions/1845482/what-is-uintptr-t-data-type

or is there something specifically compatible with ctypes?

[Edgar 't Hart]

“long*” would also work. Or even a void*, I don’t know how the variable is used. Since it is used for containing a pointer, and it was a “long”, I guess there will be reinterpret_cast<..>'s.

So void*, or long* will both probably work.

[Rene van Paassen]

I just tried, it didn’t work.

The pointer value is the key for keeping and finding references to the associated objects that are kept in a weakref dict. Cython complains that it cannot convert the pointers to python objects.

The pointer value also seems to be used to call back through the C interface.

And yes, there is some casting there.

The people behind Linux and OSX had the foresight to make “long” equal to the pointer size; that is why it simply worked there.

[Edgar 't Hart]

Can you use size_t? it is unsigned and the size 32bit on x86 vs 64bit on x64

[Rene van Paassen]

updated patch, uses size_t

[Rene van Paassen]

The packaged ode just became available on conda-forge

more info on https://github.com/conda-forge/libode-feedstock

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[Oleh Derevenko]

Merged into trunk with revision 2203

[Oleh Derevenko]

Also, the patch has been merged into “0.16.x” branch with revision 2205

[Oleh Derevenko]

Removing version: 0.16 (automated comment)