Cython 编译在 jupyter 笔记本中静默失败

Question

每当我将导入导入 c++ 库时，Cython 编译都会静默失败

%% cython -a --verbose
from libcpp.string cimport string

编译运行，但没有显示注释，如果你定义了一个函数，下一个单元格就找不到它。

输出：

[1/1] Cythonizing /Users/jorenvs/.ipython/cython/_cython_magic_88bf31fdc881aa1e28333abb92cb8079.pyx
building '_cython_magic_88bf31fdc881aa1e28333abb92cb8079' extension
clang -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/include -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Tk.framework/Versions/8.5/Headers -I/usr/local/lib/python3.7/site-packages/numpy/core/include -I/usr/local/lib/python3.7/site-packages/numpy/core/include -I/usr/local/lib/python3.7/site-packages/numpy/core/include -I/usr/local/lib/python3.7/site-packages/numpy/core/include -I/usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/include/python3.7m -c /Users/jorenvs/.ipython/cython/_cython_magic_88bf31fdc881aa1e28333abb92cb8079.c -o /Users/jorenvs/.ipython/cython/Users/jorenvs/.ipython/cython/_cython_magic_88bf31fdc881aa1e28333abb92cb8079.o

Answer 1

我发现编译失败的原因有很多，而且它们通常是沉默的。如果您无法使用 CLI cython 重现它，找出失败原因的最简单方法是手动运行详细的 clang 命令。这应该会给你确切的错误。

在我的情况下是这样的：

$ clang -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/include -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Tk.framework/Versions/8.5/Headers -I/usr/local/lib/python3.7/site-packages/numpy/core/include -I/usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/include/python3.7m -c /Users/jorenvs/.ipython/cython/_cython_magic_a57fa1e560b400e6a28c993dfc83bfc5.c -o /Users/jorenvs/.ipython/cython/Users/jorenvs/.ipython/cython/_cython_magic_a57fa1e560b400e6a28c993dfc83bfc5.o

In file included from /Users/jorenvs/.ipython/cython/_cython_magic_a57fa1e560b400e6a28c993dfc83bfc5.c:630:
In file included from /usr/local/lib/python3.7/site-packages/numpy/core/include/numpy/arrayobject.h:4:
In file included from /usr/local/lib/python3.7/site-packages/numpy/core/include/numpy/ndarrayobject.h:12:
In file included from /usr/local/lib/python3.7/site-packages/numpy/core/include/numpy/ndarraytypes.h:1830:
/usr/local/lib/python3.7/site-packages/numpy/core/include/numpy/npy_1_7_deprecated_api.h:17:2: warning: "Using deprecated NumPy API, disable it with " "#define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION" [-W#warnings]
#warning "Using deprecated NumPy API, disable it with " \
 ^
/Users/jorenvs/.ipython/cython/_cython_magic_a57fa1e560b400e6a28c993dfc83bfc5.c:633:10: fatal error: 'ios' file not found
#include "ios"
         ^~~~~
1 warning and 1 error generated.

这让我想到了这个问题：Compiling cython with gcc: No such file or directory from #include "ios"

因此，我的解决方案，添加 c++ 语言规范：

%% cython -a --verbose
#distutils: language = c++
from libcpp.string cimport string