Question

我正在尝试编译Cython代码并将其用作Python模块。我跟着Cython's basic tutorial。我发了文件hellowolrd.pyx：

print "Hello World"

我做了setup.py：

from distutils.core import setup
from Cython.Build import cythonize

setup(
    ext_modules = cythonize("helloworld.pyx")
)

并运行：

python setup.py build_ext --inplace

但不幸的是发生了一个错误：

running build_ext
building 'helloworld' extension
gcc -pthread -Wno-unused-result -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -O2 -g -pipe -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -g -O2 -g -pipe -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -I/usr/include/ncursesw -fPIC -I/usr/include/python3.5m -c helloworld.c -o build/temp.linux-x86_64-3.5/helloworld.o
gcc -pthread -shared -Wl,--as-needed -Wl,-z,relro -Wl,-O1 -Wl,--build-id -Wl,--enable-new-dtags build/temp.linux-x86_64-3.5/helloworld.o -L/usr/lib64 -lpython3.5m -o /home/dima/Projects/AntennaModeling/test/helloworld.cpython-35m-x86_64-linux-gnu.so
/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-mageia-linux-gnu/5.4.0/../../../libpython3.5m.so when searching for -lpython3.5m
/bin/ld: skipping incompatible /lib/libpython3.5m.so when searching for -lpython3.5m
/bin/ld: skipping incompatible /usr/lib/libpython3.5m.so when searching for -lpython3.5m
/bin/ld: cannot find -lpython3.5m
collect2: error: command ld failed with exit status 1
error: command 'gcc' failed with exit status 1

似乎gcc对python3.5库不满意。我尝试使用以下命令编译而没有distutils：

cython -a helloworld.pyx
gcc -shared -pthread -fPIC -fwrapv -O2 -Wall -fno-strict-aliasing -I/usr/include/python3.5m -o helloworld.so helloworld.c

它有效。从知道我可以从Python解释器导入helloworld。但我无法弄清楚如何使用distutils编译Cython代码。我试图使用extra_compile_args传递相同的标志但它没有用。

UPD：它发现gcc找不到64位的python库，所以试图明确地显示库目录。所以我改变了setup.py

from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize

extensions = [
        Extension("helloworld", ["helloworld.pyx"],
        library_dirs = ['/usr/lib64']),
        ]
setup(
    name = 'Hello world app',
    ext_modules = cythonize(extensions),
)

仍然是相同的输出

running build_ext
building 'helloworld' extension
gcc -pthread -Wno-unused-result -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -O2 -g -pipe -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -g -O2 -g -pipe -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -I/usr/include/ncursesw -fPIC -I/usr/include/python3.5m -c helloworld.c -o build/temp.linux-x86_64-3.5/helloworld.o
gcc -pthread -shared -Wl,--as-needed -Wl,-z,relro -Wl,-O1 -Wl,--build-id -Wl,--enable-new-dtags build/temp.linux-x86_64-3.5/helloworld.o -L/usr/lib64 -L/usr/lib64 -lpython3.5m -o /home/dima/Projects/AntennaModeling/test/helloworld.cpython-35m-x86_64-linux-gnu.so
/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-mageia-linux-gnu/5.4.0/../../../libpython3.5m.so when searching for -lpython3.5m
/bin/ld: skipping incompatible /lib/libpython3.5m.so when searching for -lpython3.5m
/bin/ld: skipping incompatible /usr/lib/libpython3.5m.so when searching for -lpython3.5m
/bin/ld: cannot find -lpython3.5m
collect2: error: command ld failed with exit status 1
error: command 'gcc' failed with exit status 1

Answer 1

通常，链接器会搜索名称为libXXX.so而不是libXXX.so.1.0的库（如果不成功，则搜索名称为libXXX.a的库）。通常libXXX.so是libXXX.so.Y.0的符号链接，它是真正的库。

您可以通过使用-Wl,--verbose调用link-command来查看链接器，例如：

gcc -Wl,--verbose -pthread -shared -Wl,--as-needed -Wl,-z,relro -Wl,-O1 -Wl,--build-id -Wl,--enable-new-dtags build/temp.linux-x86_64-3.5/helloworld.o -L/usr/lib64 -lpython3.5m -o /home/dima/Projects/AntennaModeling/test/helloworld.cpython-35m-x86_64-linux-gnu.so

你会看到类似的东西：

...
attempt to open /usr/lib64/libpython3.5m.so failed
...

所以有两种选择：

答：在你的系统上引入符号链接/usr/lib64/libpython3.5m.so。

或更少侵入性B：将libraries=[':libpython3.5m.so.1.0']添加到您的扩展名定义中：

extensions = [
        Extension("helloworld", ["helloworld.pyx"],
        library_dirs = ['/usr/lib64']),
        libraries=[':libpython3.5m.so.1.0']
        ]

现在，链接命令应该看起来有点不同：

 gcc ... -L/usr/lib64 -l:libpython3.5m.so.1.0 ...

链接器将查找libpython3.5m.so.1.0，而不仅仅是libpython3.5m.so仍由distutils提供。

使用distutils编译Cython代码时出现问题

1 个答案: