Python dll Extension Import

Question

I created extensions for my Python and created a abcPython.dll. How can I import this dll into my Python scripts?

I get an error message when I try to import it usin the following command

>>>import abcPython
>>>Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     ImportError: No module named abcPython
>>>

I manually created a system environment variable named PYTHONPATH which stores the path to the abcPython.dll, but still the error remains.

How can I fix this?

Hello hello ... Did you get your problem fixed? Do you plan to accept an answer? — John Machin, Jan 11 '10 at 22:45

score 13 · Answer 1 · edited May 23 '17 at 11:53

Follow Building C and C++ Extensions on Windows carefully - in sub-section 7, it says:

The output file should be called spam.pyd (in Release mode) or spam_d.pyd (in Debug mode). The extension .pyd was chosen to avoid confusion with a system library spam.dll to which your module could be a Python interface
...
Changed in version 2.5: Previously, file names like spam.dll (in release mode) or spam_d.dll (in debug mode) were also recognized.

Try the renaming your DLL to use a .pyd extension instead of .dll.

(thanks, Peter Hansen)

The reference points to a C example, which explicitly includes an INIT function, PyMODINIT_FUNC initexample(void). The resulting DLL should be renamed example.pyd :

#include "Python.h"

static PyObject *
ex_foo(PyObject *self, PyObject *args)
{
    printf("Hello, world\n");
    Py_INCREF(Py_None);
    return Py_None;
}

static PyMethodDef example_methods[] = {
    {"foo", ex_foo, METH_VARARGS, "foo() doc string"},
    {NULL, NULL}
};

PyMODINIT_FUNC
initexample(void)
{
    Py_InitModule("example", example_methods);
}

Thanks for replying I renamed the .dll to .pyd and then tried the following >>> import abcPython Traceback (most recent call last): File "", line 1, in ImportError: dynamic module does not define init function (PyInit_abcPython) >>> — user240840, Jan 07 '10 at 12:40
Follow instructions in the linked reference and DEFINE an init function! — gimel, Jan 07 '10 at 13:24

score 2 · Answer 2 · answered Jan 08 '10 at 13:46

Aarrgghh! Yet another 2.X/3.X gotcha. RTFErrorMessage:

ImportError: dynamic module does not define init function (PyInit_abcPython)

Note the prefix: it's not init, it's PyInit_

See the 3.1 docs ... "The initialization function must be named PyInit_name(), where name is the name of the module"

score 1 · Answer 3 · edited Jan 05 '12 at 21:24

1

Simple renaming of .dll to .pyd did not help. I was using SWIG to create the extension module. I created a .pyd instead of creating a .dll module and that solved the issue.

edited Jan 05 '12 at 21:24

cdeszaq

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answered Feb 16 '10 at 09:55

user240840

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score 0 · Answer 4 · answered Jul 17 '14 at 11:53

0

As an example: Imagine you have compiled OpenCV and have several *.dll and the cv2.pyd file.

You need to copy those files to 'DLLs' folder within the python directory.

Then import the module to check wether it is ok.

answered Jul 17 '14 at 11:53

Nuno Aniceto

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Python dll Extension Import

4 Answers4

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