Failed to import a "pyd: File When python intepreter embed in C++ project

Junze Liu liujz39 at gmail.com
Thu Jan 24 03:43:50 CET 2013


On Thursday, January 24, 2013 12:28:58 AM UTC+8, Leonard, Arah wrote:
> > I create a pyd File named "testPyd" with boostPython,and then I import the testPyd module into "test.py", it works perfect!
> 
> > But when I embeded the python interpreter into my C++ project and run the "test.py", it comes out a "ImportErr: no module named testPyd".
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> > It has confused me for two days and I googled for long time,but I can't find the answer!
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> > Anybody here can help me ?
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> > Thank you!
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> > 
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> 
> 
> 	Ah, that sounds familiar.  I have a small bit of experience with Boost.  I could be wrong, because once you start mixing it up with Boost all sorts of weird things can happen (especially on a MS compiler, because no one tests for Windows, let alone a pay-for compiler) but my experience has shown that if you get that specific import error, what it actually means is just that the PYD import failed for ANY reason.  It has nothing to do with the name or that the PYD couldn't be found.  Just that somewhere, at some time during import, it failed to fully load.
> 
> 
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> 	In my use a lot of times it was either that a DLL that module depended on wasn't in the path, or my favorite kicker, that some compile/link flags between the PYD and the Python interpreter don't match well enough.  (Usually from mixing debug and release builds together.)
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> 
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> 	From what I've seen anyway, the Python interpreter really doesn't like being built in a traditional debug mode, so I always do a release build of it.  It's a little inconvenient, but in the linker flags you can still set your PYDs to generate debug information even in release builds, so you can still run the debugger on them when you attach to the process of the python interpreter EXE.  And especially be sure to use the RELEASE runtime library flag (such as /MD) instead of the debug flag (such as /MDd).
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> 
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> 	That's as much as I know anyway.  Though depending, if you add any new templates/libraries into Boost (such as for NumPy ndarray), you also may need to use the /DBOOST_ALL_NO_LIB compiler macro on an MS compiler because MS doesn't adhere to template standards correctly and you often end up with multiply-defined functions if you don't use that macro.  If I remember correctly.  (It's been a while.)
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> 	That and you may be picking up variable length arrays out of your teeth, replacing chunks of code with the use of new and delete operators.  No one tests for Microsoft and the MS compiler is way behind in adhering to C/C++ standards, and VLAs pop up a lot.
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> 	Hopefully something in all of this helped.  Boost can be ... daunting.  I get it, in theory.  But in practice it often hurts my head.  ;)
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> Sincerely,
> 
> Arah Leonard

Dear Lenoard,
    Thanks for your hearty assistance, and it finally works.I just change my RELEASE Run Time Library flag to MD, then the results come out.
    Before I receive your mail, I googled for kinds of solutions and tried to solve this problem, but none of them works.Yesterday, someones said that the python module in *pyd Files* should be initialized before they can be embed into C++, and a function named init<ModuleName> should be called before importing the module, I was confused with this for a couple of hours until I saw your mail.
   I am new to boost.python.If I propose any questions that seems naive to you the other days, any suggestion from you would be more than welcome!  
   Thanks again for your help to make me out of my wrong way!

Sincerely,
George Liu



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