[英]Using Cython To Link Python To A Shared Library
I am trying to integrate a third party library written in C
with my python
application using Cython
. 我正在尝试使用
Cython
用C
编写的第三方库与我的python
应用程序Cython
。 I have all of the python code written for a test. 我已经为测试编写了所有的python代码。 I am having trouble finding an example for setting this up.
我很难找到设置此示例的方法。
I have a pyd/pyx
file I created manually. 我有一个手动创建的
pyd/pyx
文件。 The third party has given me a header file (*.h)
and a shared library (*.so)
. 第三方给了我一个
header file (*.h)
和一个shared library (*.so)
。 As far as I can tell, there are no other dependencies. 据我所知,没有其他依赖项。 Can someone provide an example of how to set this up using
Cython
and disutils
? 有人可以提供使用
Cython
和disutils
进行设置的示例吗?
Thanks 谢谢
Sure ! 当然可以!
(In the following, I assume that you already know how to deal with cimport
and the interactions between .pxd
and .pyx
. If this is not completely the case, just ask and I will develop that part as well) (在下面,我假设您已经知道如何处理
cimport
以及.pxd
和.pyx
之间的交互。如果不是完全如此,请问一下,我也将开发该部分)
The sample (grabbed from a C++ project of mine, but a C project would work pretty much the same) : 示例(来自我的C ++项目,但C项目的工作原理几乎相同):
1. The Distutils setup file : 1. Distutils安装文件:
Assuming that the extension to be created will be called myext
and the 3rd party shared library is libexternlib.so
(note the lib* prefix, here)... 假设要创建的扩展名为
myext
并且第三方共享库为libexternlib.so
(请注意lib *前缀,在此处)...
# setup.py file
import sys
import os
import shutil
from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext
# clean previous build
for root, dirs, files in os.walk(".", topdown=False):
for name in files:
if (name.startswith("myext") and not(name.endswith(".pyx") or name.endswith(".pxd"))):
os.remove(os.path.join(root, name))
for name in dirs:
if (name == "build"):
shutil.rmtree(name)
# build "myext.so" python extension to be added to "PYTHONPATH" afterwards...
setup(
cmdclass = {'build_ext': build_ext},
ext_modules = [
Extension("myext",
sources=["myext.pyx",
"SomeAdditionalCppClass1.cpp",
"SomeAdditionalCppClass2.cpp"
],
libraries=["externlib"], # refers to "libexternlib.so"
language="c++", # remove this if C and not C++
extra_compile_args=["-fopenmp", "-O3"],
extra_link_args=["-DSOME_DEFINE_OPT",
"-L./some/extra/dependency/dir/"]
)
]
)
Note : Your external .so
file is linked via the libraries
option : 注意:您的外部
.so
文件通过“ libraries
选项链接:
libraries=["externlib"] # Without the 'lib' prefix and the '.so' extension...
Note : the sources
option can be used to get some additional source files compiled. 注意:
sources
选项可用于获取一些其他源文件。
Important : myext.pxd
(do not confound with .pyd
- Windows stuff) and myext.pyx
should be in the same directory. 重要提示:
myext.pxd
(不要与.pyd
混淆-Windows东西)和myext.pyx
应该位于同一目录中。 At compile time the definition file, if it exists, is processed first ( more ). 在编译时,将首先处理定义文件(如果存在)( 更多内容 )。
2. Then run it as follows : 2.然后按以下方式运行:
After having changed directory to the one containing your myext.pxd
, your myext.pyx
, as well as the above setup.py
script : 将目录更改为包含
myext.pxd
, myext.pyx
以及上面的setup.py
脚本的目录后:
# setup.sh
# Make the "myext" Python Module ("myext.so")
CC="gcc" \
CXX="g++" \
CFLAGS="-I./some/path/to/includes/ -I../../../DEPENDENCIES/python2.7/inc -I../../../DEPENDENCIES/gsl-1.15" \
LDFLAGS="-L./some/path/to/externlib/" \
python setup.py build_ext --inplace
Where : 哪里:
libexternlib.so
is assumed to be located at ./some/path/to/externlib/
libexternlib.so
被假定为位于./some/path/to/externlib/
yourheader.h
is assumed to be located at ./some/path/to/includes/
yourheader.h
假定位于./some/path/to/includes/
Note : CFLAGS
could also have been setup using the extra_compile_args
option : 注意:
CFLAGS
也可以使用extra_compile_args
选项设置:
extra_compile_args=["-I./some/path/to/includes/", "-fopenmp", "-O3"]
Note : LDFLAGS
could also have been setup using the extra_link_args
option : 注意:还可以使用
extra_link_args
选项设置LDFLAGS
:
extra_link_args=["-L./some/path/to/externlib/", "-DSOME_DEFINE_OPT", "-L./some/extra/dependency/dir/"]
Once distutils is done with the build, you get some new files, specially the myext.cpp
, myext.h
and most importantly, the myext.so
. distutils完成构建后,您将获得一些新文件,尤其是
myext.cpp
, myext.h
,最重要的是myext.so
。
3. After that, you're good to go : 3.之后,您就可以开始:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:./some/path/to/externlib/
export PYTHONPATH=$PYTHONPATH:./some/path/to/myext/
# Run some script requiring "myext.so"
python somescript.py
Where your freshly created Python extension can be imported by its name : 新创建的Python扩展名可以通过其名称导入:
# somescript.py
import myext
from myext import PySomeFeature
...
Note about Optimization : By default -O2
is used for compiling the extension, but this can be overloaded (see above setup where -O3
is specified). 关于优化的注意事项 :缺省情况下,
-O2
用于编译扩展名,但是可以重载(请参见上面的设置,其中指定了-O3
)。
Note about Cython paths : If Cython was installed in a custom directory, you might want to add it to your environment, before all : 关于Cython路径的注意事项 :如果将Cython安装在自定义目录中,则可能需要先将其添加到您的环境中:
PYTHONPATH=$PYTHONPATH:../../../DEPENDENCIES/Cython-0.18 export PYTHONPATH;
PATH=$PATH:../../../DEPENDENCIES/Cython-0.18/bin; export PATH;
Well, hope I covered the main points... 好吧,希望我能讲到要点...
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