防止在cython中对c文件进行双重编译 [英] Prevent double compilation of c files in cython

问题描述

我正在用c库编写包装程序，该库具有几乎所有功能的文件，比如 all_funcs.c 。反过来，此文件需要编译大量其他c文件

I am writing a wrapper over c libriary and this lib has file with almost all functions, let say, all_funcs.c. This file in turn requires compilation of lots of another c files

我创建了 all_funcs.pyx 所有功能，但我也想创建一个子模块，该子模块可以访问 all_funcs.c 中的函数。现在可行的是将所有c文件添加到setup.py中的两个扩展中，但是每个c文件都编译两次：第一个用于 all_funcs.pyx ，第二个用于子模块扩展。

I have created all_funcs.pyx, where I wraped all functions, but I also want to create a submodule, that has access to functions from all_funcs.c. What works for now is adding all c-files to both Extensions in setup.py, however each c-file compiles twice: first for all_funcs.pyx and second for submodule extension.

有没有办法为每个扩展名提供通用的源文件？

Are there any ways to provide common sourse files to each Extension?

当前setup.py的示例：

Example of current setup.py:

ext_helpers = Extension(name=SRC_DIR + '.wrapper.utils.helpers',
                        sources=[SRC_DIR + '/wrapper/utils/helpers.pyx'] + source_files_paths,
                        include_dirs=[SRC_DIR + '/include/'])


ext_all_funcs = Extension(name=SRC_DIR + '.wrapper.all_funcs',
                          sources=[SRC_DIR + '/wrapper/all_funcs.pyx'] + source_files_paths,
                          include_dirs=[SRC_DIR + '/include/'])

EXTENSIONS = [
    ext_helpers,
    ext_all_funcs,
]

if __name__ == "__main__":
    setup(
        packages=PACKAGES,
        zip_safe=False,
        name='some_name',
        ext_modules=cythonize(EXTENSIONS, language_level=3)
        )

source_files_paths -包含常见c源文件的列表

source_files_paths - the list with common c source files

推荐答案

注意：此答案仅说明如何避免使用的库参数对c / cpp文件进行多次编译设置功能。但是，它没有说明如何避免由于违反ODR而导致的可能问题-有关此问题，请参见此SO-post 。

Note: this answer only explains how to avoid multiple compilation of c/cpp-files using libraries-argument of setup-function. It doesn't however explain how to avoid possible problems due to ODR-violation - for that see this SO-post.

在设置中添加库参数将触发在构建 ext_modules 之前构建build_clib （运行 setup.py build 或<$ c时） $ c> setup.py install 命令），则在扩展名被链接时，生成的 static 库也将自动传递给链接器。

Adding libraries-argument to setup will trigger build_clib prior to building of ext_modules (when running setup.py build or setup.py install commands), the resulting static library will also be automatically passed to the linker, when extensions are linked.

对于您的 setup.py ，这意味着：

from setuptools import setup, find_packages, Extension
...
#common c files compiled to a static library:
mylib = ('mylib', {'sources': source_files_paths}) # possible further settings

# no common c-files (taken care of in mylib):
ext_helpers = Extension(name=SRC_DIR + '.wrapper.utils.helpers',
                        sources=[SRC_DIR + '/wrapper/utils/helpers.pyx'],
                        include_dirs=[SRC_DIR + '/include/'])

# no common c-files (taken care of in mylib):
ext_all_funcs = Extension(name=SRC_DIR + '.wrapper.all_funcs',
                          sources=[SRC_DIR + '/wrapper/all_funcs.pyx'],
                          include_dirs=[SRC_DIR + '/include/'])

EXTENSIONS = [
    ext_helpers,
    ext_all_funcs,
]

if __name__ == "__main__":
    setup(
        packages=find_packages(where=SRC_DIR),
        zip_safe=False,
        name='some_name',
        ext_modules=cythonize(EXTENSIONS, language_level=3),
        # will be build as static libraries and automatically passed to linker:
        libraries = [mylib] 
        )

要就地构建扩展，应该调用：

To build the extensions inplace one should invoke:

python setupy.py build_clib build_ext --inplace

仅凭 build_ext 是不够的：我们需要先构建静态库，然后才能将其用于扩展程序。

as build_ext alone is not enough: we need the static libraries to build before they can be used in extensions.

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