So, I've searched all around the web and I couldn't find anything.
I'm started with python, and I made a TKinter application. At first, I tried to compile it to an .exe file, but that didn't work. So now I'm embedding python in C++. Every single time I try to compile it (using Dev-C++), I get the error:
C:\Users\*****\AppData\Local\Temp\ccsqSJ5V.o [program-name].cpp:(.text+0x10): undefined reference to `__imp_Py_Initialize'
C:\Users\*****\AppData\Local\Temp\ccsqSJ5V.o [program-name].cpp:(.text+0x25): undefined reference to `__imp_PyRun_SimpleStringFlags'
C:\Users\*****\AppData\Local\Temp\ccsqSJ5V.o [program-name].cpp:(.text+0x2e): undefined reference to `__imp_Py_Finalize'
F:\Documents\Videos\[program-name]\program\collect2.exe [Error] ld returned 1 exit status
F: stands for the flash drive.
In the Dev-c++ options, I added:
-Wall -I\C:\Users\*****\AppData\Local\Programs\Python\Python35\include
So this is the full command:
g++.exe "F:\Documents\Videos\[program-name]\program\[program-name].cpp" -o "F:\Documents\Videos\[program-name]\program\[program-name].exe" -Wall -I\C:\Users\*****\AppData\Local\Programs\Python\Python35\include -I"C:\Programma's\Dev-C++\MinGW64\include" -I"C:\Programma's\Dev-C++\MinGW64\x86_64-w64-mingw32\include" -I"C:\Programma's\Dev-C++\MinGW64\lib\gcc\x86_64-w64-mingw32\4.9.2\include" -I"C:\Programma's\Dev-C++\MinGW64\lib\gcc\x86_64-w64-mingw32\4.9.2\include\c++" -I"C:\Users\*****\AppData\Local\Programs\Python\Python35\include" -L"C:\Programma's\Dev-C++\MinGW64\lib" -L"C:\Programma's\Dev-C++\MinGW64\x86_64-w64-mingw32\lib" -static-libgcc
My question is: how do I deal with this?
And please note: I haven't got administrator privileges, I'm just a standard user.
Python version: 3.5.1
Dev-C++ version: 5.11
GCC version: I don't know, but I'll find it out if needed :)
EDIT: Because of the duplicate mark by NathanOliver, I'll ask it like this: which command line variables do I have to add to compile it?
The linker is complaining bacause it can't find a group of references about some python stuff, as a matter of fact I don't see any python library in the g++ invocation.
You need to had something like this -lpython3.5.1 to tell g++ to link against the python library (assuming python is installed in your system, else you will have to add the path to the library using the -L option).
More resources on g++ makefiles and linking:
https://www3.ntu.edu.sg/home/ehchua/programming/cpp/gcc_make.html
I am trying to compile winrandom and got the followint error.
Please help - what could be the reason?
c:\MinGW\bin\gcc.exe -shared -s build\temp.win32-3.4\Release\src\winrandom.o bui
ld\temp.win32-3.4\Release\src\winrandom.def -LC:\Python34\libs -LC:\Python34\PCb
uild -lCrypt32 -lpython34 -lmsvcr100 -o build\lib.win32-3.4\winrandom.pyd
Cannot export PyInit_winrandom: symbol not defined
build\temp.win32-3.4\Release\src\winrandom.o:winrandom.c:(.text+0x437): undefine
d reference to `Py_InitModule'
collect2.exe: error: ld returned 1 exit status
error: command 'c:\\MinGW\\bin\\gcc.exe' failed with exit status 1
Py_InitModule is no longer used in Python 3.X, the package you downloaded is probably for Python 2.X. That is where you issue lies. Try finding a version that is meant for Python 3.X
I am trying to follow an example for Cython builds from here http://blog.perrygeo.net/2008/04/19/a-quick-cython-introduction/, except my c1.pyx is simply helloworld.pyx with "print "Hello World"":
# this will create a c1.c file - the C source code to build a python extension
cython c1.pyx
# Compile the object file
gcc -c -fPIC -I/usr/include/python2.5/ c1.c
# Link it into a shared library
gcc -shared c1.o -o c1.so
The reason I am doing it in the command line is because my setup.py is giving me an error so I am doing it manually to see what is wrong.
The last step (gcc -shared c1.o -o c1.so) is where I hit the following error:
c:/users/MyName/anaconda/mingw/bin/../lib/gcc/x86_64-w64-mingw32/4.7.0/../../../..
/x86_64-w64-mingw32/bin/ld.exe: cannot find -lgcc
c:/users/MyName/anaconda/mingw/bin/../lib/gcc/x86_64-w64-mingw32/4.7.0/../../../..
/x86_64-w64-mingw32/bin/ld.exe: cannot find -lgcc
collect2.exe: error: ld returned 1 exit status
error: command 'C:\\Users\\MyName\\Anaconda\\Scripts\\gcc.bat' failed with exit st
atus 1
Any suggestions?
EDIT1: Thank you #mat for the edit. Also, I was noticing I didn't have Visual C++ 2008 installed on my computer. Not sure if Anaconda requires this for GCC and if this is the solution.
I am trying to compile a software called MRtrix in windows. It uses a python build script, (I have uploaded it here: http://pastebin.com/XnufSz53)
when I run this script I get the error pasted bellow.
I guess that the GSL libraries are not being found and I need to add a -L pointing to the library but because the compilation is being done by the python script I do not really now how to do this. Currently GnuWin is installed at C:\GnuWin32\
Thank you in advance,
Jesse
============================================================
ERROR: [LD] lib\mrtrix-0_2_11.dll
g++ -shared lib\image\format\base.o lib\math\vector.o lib\file\mmap.o lib\args.o
lib\image\format\dicom.o lib\file\dicom\select_cmdline.o lib\file\key_value.o l
ib\image\axis.o lib\image\format\mrtrix.o lib\image\interp.o lib\data_type.o lib
\point.o lib\image\mapper.o lib\file\dicom\element.o lib\file\dicom\mapper.o lib
\file\dicom\patient.o lib\file\dicom\quick_scan.o lib\image\object.o lib\mrtrix.
o lib\image\format\xds.o lib\file\dicom\dict.o lib\app.o lib\math\matrix.o lib\f
ile\config.o lib\image\format\mri.o lib\file\dicom\image.o lib\math\linalg.o lib
\file\dicom\study.o lib\file\dicom\series.o lib\image\name_parser.o lib\image\fo
rmat\list.o lib\file\dicom\tree.o lib\image\fft.o lib\image\header.o lib\image\f
ormat\analyse.o lib\image\format\nifti1.o -LC:/gtkmm64/lib -lglibmm-2.4 -lgobjec
t-2.0 -lsigc-2.0 -lgthread-2.0 -lglib-2.0 -lintl -lgsl -lgslcblas -lz -o lib\mrt
rix-0_2_11.dll
failed with output:
c:/mingw/bin/../lib/gcc/mingw32/4.7.2/../../../../mingw32/bin/ld.exe: cannot fin
d -lgsl
c:/mingw/bin/../lib/gcc/mingw32/4.7.2/../../../../mingw32/bin/ld.exe: cannot fin
d -lgslcblas
collect2.exe: error: ld returned 1 exit status
============================================================
So I have a few Python C extensions I have previously built for and used in 32 bit Python running in Win7. I have now however switched to 64 bit Python, and I am having issues building the C extension with MinGW-w64.
I made the changes to distutils as per this post, but I am getting some weird errors suggesting something is wrong:
$ python setup.py build
running build
running build_ext
building 'MyLib' extension
c:\MinGW64\bin\x86_64-w64-mingw32-gcc.exe -mdll -O -Wall -Ic:\Python27\lib\site-packages\numpy\core\include -Ic:\Python27\include -Ic:\Python27\PC -c MyLib.c -o build\temp.win-amd64-2.7\Release\mylib.o
MyLib.c: In function 'initMyLib':
MyLib.c:631:5: warning: implicit declaration of function 'Py_InitModule4_64' [-Wimplicit-function-declaration]
writing build\temp.win-amd64-2.7\Release\MyLib.def
c:\MinGW64\bin\x86_64-w64-mingw32-gcc.exe -shared -s build\temp.win-amd64-2.7\Release\mylib.o build\temp.win-amd64-2.7\Release\MyLib.def -Lc:\Python27\libs -Lc:\Python27\PCbuild\amd64 -lpython27 -o build\lib.win-amd64-2.7\MyLib.pyd
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x13d): undefined reference to `__imp_PyExc_ValueError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x1275): undefined reference to `__imp_PyExc_ValueError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x1eef): undefined reference to `__imp_PyExc_ImportError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x1f38): undefined reference to `__imp_PyExc_AttributeError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x1f4d): undefined reference to `__imp_PyCObject_Type'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x1f61): undefined reference to `__imp_PyExc_RuntimeError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x1fc7): undefined reference to `__imp_PyExc_RuntimeError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x1ffe): undefined reference to `__imp_PyExc_RuntimeError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x2042): undefined reference to `__imp_PyExc_RuntimeError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x206c): undefined reference to `__imp_PyExc_RuntimeError'
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x208a): more undefined references to `__imp_PyExc_RuntimeError' follow
build\temp.win-amd64-2.7\Release\mylib.o:MyLib.c:(.text+0x20a7): undefined reference to `__imp_PyExc_ImportError'
collect2.exe: error: ld returned 1 exit status
error: command 'x86_64-w64-mingw32-gcc' failed with exit status 1
I have googled around quite a bit to find information, but it's not easy to find a definite answer. Could someone shed some light on this? What further changes should I do to be able to successfully build C extensions for 64 bit Python in Win7?
EDIT:
After some helpful pointers in cgohlke's comments below I managed to generate libpython27.a. However after following the advice on this post (2nd to last) I still had a the __imp_Py_InitModule4_64 error. After some serious Google-fu I managed to trip over this post telling me to rename the Py_InitModule4 line to Py_InitModule4_64. After that everything worked swimmingly.
This worked for me with Python 3.3 :
create static python lib from dll
python dll is usually in C:/Windows/System32; in msys shell:
gendef.exe python33.dll
dlltool.exe --dllname python33.dll --def python33.def --output-lib libpython33.a
mv libpython33.a C:/Python33/libs
use swig to generate wrappers
e.g., swig -c++ -python myExtension.i
wrapper MUST be compiled with MS_WIN64, or your computer will crash when you import the class in Python
g++ -c myExtension.cpp -I/other/includes
g++ -DMS_WIN64 -c myExtension_wrap.cxx -IC:/Python33/include
shared library
g++ -shared -o _myExtension.pyd myExtension.o myExtension_wrap.o -lPython33 -lOtherSharedLibs -LC:/Python33/libs -LC:/path/to/other/shared/libs
make sure all shared libs (gdal, OtherSharedLibs) are in your PATH
(windows does not use LD_LIBRARY_PATH or PYTHONPATH)
in Python, just: import myExtension
voila!
I realize this is an old question, but it is still the top search result. Today, in 2019, I was able to do this:
https://github.com/PetterS/quickjs/commit/67bc2428b8c0716538b4583f4f2b0a2a5a49106c
In short:
Make sure a 64-bit version of mingw-w64 is in the PATH.
Monkey-patch distutils:
import distutils.cygwinccompiler
distutils.cygwinccompiler.get_msvcr = lambda: []
Some differences in the shell w.r.t. escaping.
extra_link_args = ["-Wl,-Bstatic", "-lpthread"] in order to link statically and not have extra runtime deps.
pipenv run python setup.py build -c mingw32 now works.
Here is a example code for VC++ Build Tools
https://github.com/starnight/python-c-extension/tree/master/00-HelloWorld
You could try:
python setup.py -c mingw32
However this is not work for me.
My Solution is:
install Anaconda 64bit python 3.6
install mingw64
add mingw64/bin to PATH
compile dll from c file by
gcc -c libmypy.c -IC:\Users\{user_name}\Anaconda3\pkgs\python-3.6.4-h6538335_1\include
gcc -shared -o libmypy.dll libmypy.o -LC:\Users\{user_name}\Anaconda3\pkgs\python-3.6.4-h6538335_1\libs -lPython36
load dll file in .py script
from ctypes import *
m = cdll.LoadLibrary(r"C:\{path_to_dll}\libmypy.dll")
print(m.hello())
I created a monkey-patch for setuptools to let you to build_ext with mingw64 on Windows easily. See https://github.com/imba-tjd/mingw64ccompiler
I used this thread to wade through learning how to make a C extension, and since most of what I learned is in it, I thought I'd put the final discovery here too, so that someone else can find it if they are looking.
I wasn't trying to compile something big, just the example in Hetland's Beginning Python. Here is what I did (the example C pgm is called palindrome.c). I'm using Anaconda with python 3.7 in it, and the TDM-GCC version of MinGW64. I put all of the tools used into my Path, and all of the paths needed in PYTHONPATH, and the ..\Anaconda3 directory into PYTHON_HOME. I still ended up using explicit paths on some things.
I created the libpython37.a library with gendef.exe and dlltool.exe as Mark said above, and put it in ..\Anaconda3\libs.
I followed the prescription in Hetland:
gcc -c palindrome.c
gcc -I$PYTHON_HOME -I$PYTHON_HOME/Include -c palindrome_wrap.c
The second failed, the compiler couldn't find Python.h, the following worked:
gcc -I[somedirectories]\Anaconda3\Include -c palindrome_wrap.c
I then did, as many have said, including Hetland 3rd ed.,
gcc -shared palindrome.o palindrome_wrap.o [somedirectories]/Anaconda3/libs/libpython37.a -o _palindrome.dll
This did not work. Even with the Load Library cswu used (which I found elsewhere, too).
So I gendef'd _palindrome.dll and couldn't find the function in it, "is_palindrome" in the exports. I went through some of the SWIG documentation, and declared the function both in the %{ %} section and below it, both extern, that finally got the function extern'd in palindrome_wrap.c as it should have been. But no export, so I went back into palindrome.c and redeclared the function as:
declspec(dllexport) extern int __stdcall is_palindrome(char* text)
and redeclared it in palindrome.i in both places as above with this signature.
Partial success! It got listed in the Export section when I gendef'd _palindrome.dll and I could do cswu's call using Load Library. But still not do what Hetland says and do
import _palindrome
in Python.
Going back to all the sources again, I could not figure this out. I finally started reading the SWIG documentation from the beginning leaving no stone unturned -- Searching through the manual doesn't produce the place found.
At the end of Introduction Sec. 2.7 Incorporating Into a Build System, under the sample Make process, it says:
"The above example will generate native build files such as makefiles, nmake files and Visual Studio projects which will invoke SWIG and compile the generated C++ files into _example.so (UNIX) or _example.pyd (Windows). For other target languages on Windows a dll, instead of a .pyd file, is usually generated."
And that's the answer to the last problem:
The compile step for the dll should read:
gcc -shared palindrome.o palindrome_wrap.o [somedirectories]/Anaconda3/libs/libpython37.a -o _palindrome.pyd
(I didn't go back and change out my declspec declarations so I don't know whether they were necessary, so they were still there too).
I got a file, _palindrome.pyd
Which if in the PYTHONPATH (mine was local) works, and one can then do
import _palindrome
from _palindrome import is_palindrome
and use the exported, properly wrapped and packaged C function, compiled with TDM-GCC, in python as promised. gcc, which is MinGW64 in a different installation, knows how to do the .pyd file. I diffed the dll and pyd since they were the same byte length. They are not the same at hundreds of points.
Hope this helps someone else.