我试图设置我的Cygwin环境，以使用pyenv来管理python版本。我没有管理员权限，因此我使用--no-admin标志运行安装程序。
我使用Cygwin软件包管理器应用程序解决了一些依赖关系。但是我被困在这个问题上： ModuleNotFoundError：没有名为'_ctypes'的模块
我尝试按照发现的许多讨论中的建议安装libffi和libffi-devel。在Cygwin中，它似乎不起作用，或者至少pyenv没有使用它们。
有人可以帮忙吗？
命令：pyenv install 3.7.4 --verbose
输出：
---------- (...) ----------
./python.exe -E ./setup.py install \
--prefix=/home/paulo.amaral/.pyenv/versions/3.7.4 \
--install-scripts=/home/paulo.amaral/.pyenv/versions/3.7.4/bin \
--install-platlib=/home/paulo.amaral/.pyenv/versions/3.7.4/lib/python3.7/lib-dynload \
--root=/
running install
running build
running build_ext
ldd: /lib/libreadline.a: Permission denied
INFO: Can't locate Tcl/Tk libs and/or headers
building '_crypt' extension
gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -I/home/paulo.amaral/.pyenv/versions/3.7.4/include -I./Include -I. -I/home/paulo.amaral/.pyenv/versions/3.7.4/include -I/tmp/python-build.20190723112712.51525/Python-3.7.4/Include -I/tmp/python-build.20190723112712.51525/Python-3.7.4 -c /tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_cryptmodule.c -o build/temp.cygwin-3.0.7-x86_64-3.7/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_cryptmodule.o
gcc -shared -Wl,--enable-auto-image-base -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -I/home/paulo.amaral/.pyenv/versions/3.7.4/include build/temp.cygwin-3.0.7-x86_64-3.7/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_cryptmodule.o -L. -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -L/usr/local/lib -L. -lpython3.7m -o build/lib.cygwin-3.0.7-x86_64-3.7/_crypt.dll
build/temp.cygwin-3.0.7-x86_64-3.7/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_cryptmodule.o: In function `crypt_crypt_impl':
/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_cryptmodule.c:43: undefined reference to `crypt'
/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_cryptmodule.c:43:(.text+0x34): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `crypt'
collect2: error: ld returned 1 exit status
building '_uuid' extension
gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -I/home/paulo.amaral/.pyenv/versions/3.7.4/include -I/usr/include/uuid -I./Include -I. -I/home/paulo.amaral/.pyenv/versions/3.7.4/include -I/tmp/python-build.20190723112712.51525/Python-3.7.4/Include -I/tmp/python-build.20190723112712.51525/Python-3.7.4 -c /tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_uuidmodule.c -o build/temp.cygwin-3.0.7-x86_64-3.7/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_uuidmodule.o
gcc -shared -Wl,--enable-auto-image-base -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -I/home/paulo.amaral/.pyenv/versions/3.7.4/include build/temp.cygwin-3.0.7-x86_64-3.7/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_uuidmodule.o -L. -L/home/paulo.amaral/.pyenv/versions/3.7.4/lib -L/usr/local/lib -L. -lpython3.7m -o build/lib.cygwin-3.0.7-x86_64-3.7/_uuid.dll
build/temp.cygwin-3.0.7-x86_64-3.7/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_uuidmodule.o: In function `py_uuid_generate_time_safe':
/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_uuidmodule.c:22: undefined reference to `uuid_generate_time_safe'
/tmp/python-build.20190723112712.51525/Python-3.7.4/Modules/_uuidmodule.c:22:(.text+0xe): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `uuid_generate_time_safe'
collect2: error: ld returned 1 exit status
INFO: Could not locate ffi libs and/or headers
Python build finished successfully!
The necessary bits to build these optional modules were not found:
_gdbm _lzma _sqlite3
_tkinter nis ossaudiodev
spwd
To find the necessary bits, look in setup.py in detect_modules() for the module's name.
The following modules found by detect_modules() in setup.py, have been
built by the Makefile instead, as configured by the Setup files:
_abc atexit pwd
time
Failed to build these modules:
_crypt _ctypes _uuid
---------- (...) ----------
BUILD FAILEDTraceback (most recent call last):
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/ensurepip/__main__.py", line 5, in <module>
sys.exit(ensurepip._main())
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/ensurepip/__init__.py", line 204, in _main
default_pip=args.default_pip,
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/ensurepip/__init__.py", line 117, in _bootstrap
return _run_pip(args + [p[0] for p in _PROJECTS], additional_paths)
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/ensurepip/__init__.py", line 27, in _run_pip
import pip._internal
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/__init__.py", line 40, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/cli/autocompletion.py", line 8, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/cli/main_parser.py", line 12, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/commands/__init__.py", line 6, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/commands/completion.py", line 6, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/cli/base_command.py", line 20, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/download.py", line 37, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/utils/glibc.py", line 3, in <module>
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/ctypes/__init__.py", line 7, in <module>
from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'
make: *** [Makefile:1132: install] Error 1
(CYGWIN_NT-10.0 3.0.7(0.338/5/3) using python-build 1.2.13)
Inspect or clean up the working tree at /tmp/python-build.20190723094240.13485
Results logged to /tmp/python-build.20190723094240.13485.log
Last 10 log lines:
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/cli/main_parser.py", line 12, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/commands/__init__.py", line 6, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/commands/completion.py", line 6, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/cli/base_command.py", line 20, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/download.py", line 37, in <module>
File "/tmp/tmp_1p71jx7/pip-19.0.3-py2.py3-none-any.whl/pip/_internal/utils/glibc.py", line 3, in <module>
File "/tmp/python-build.20190723094240.13485/Python-3.7.4/Lib/ctypes/__init__.py", line 7, in <module>
from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'
make: *** [Makefile:1132: install] Error 1
答案 0 :(得分：0)
我找到了一种在pyenv中映射预安装的python二进制文件的解决方案（不使用pyenv install <version>），但是，它仅适用于使用setup-x86_64.exe安装的python版本。在Cygwin中编译Python非常麻烦。
git clone https://github.com/pyenv/pyenv.git ~/.pyenv
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
使用setup-x86_64.exe安装Python。对于此示例，我安装了以下软件包：
python3（版本3.6.9）python36-pip python36-virtualenv（可选，如果您使用virtualenv的话）要向pyenv手动添加现有的python版本，请创建一个文件夹.pyenv/versions/<your-version-name>/bin并在其中添加指向二进制文件的链接：
mkdir ~/.pyenv/versions/3.6.9/bin/
cd ~/.pyenv/versions/3.6.9/bin/
ln -s /usr/bin/python3.6m.exe python3.6
ln -s python3.6 python3
ln -s python3 python
ln -s /usr/bin/pip3.6 pip3.6
ln -s pip3.6 pip3
ln -s pip3 pip
ln -s /usr/bin/virtualenv-3.6 virtualenv-3.6
ln -s virtualenv-3.6 virtualenv-3
ln -s virtualenv-3 virtualenv
PS：我想可以通过常规Windows系统安装其他python版本，并在cygwin中同样进行符号链接。
答案 1 :(得分：0)
即使您已安装libffi-devel（首先需要 ），由于以下原因，您仍无法编译_ctypes和某些其他扩展模块众所周知的bug in distutils，用于查找将扩展模块与第三方库（例如libffi）的要求链接所需的导入库。
有一个最近更新的pull request可以解决此问题，已经等待了将近两年的审查。如果您想测试PR，并可能在PR上添加注释以确认它可以正常工作并且是必需的，那么它可能会有助于将PR合并起来...