Python 在 OS X 上使用 pip 安装 bcrypt 时出错：找不到 ffi.h（安装了 libffi）

Error installing bcrypt with pip on OS X: can't find ffi.h (libffi is installed)

提问by Cody

I'm getting this error when trying to install bcrypt with pip. I have libffi installed in a couple places (the Xcode OS X SDK, and from homebrew), but I don't know how to tell pip to look for it. Any suggestions?

尝试使用 pip 安装 bcrypt 时出现此错误。我在几个地方（Xcode OS X SDK 和自制软件）安装了 libffi，但我不知道如何告诉 pip 查找它。有什么建议？

Downloading/unpacking bcrypt==1.0.2 (from -r requirements.txt (line 41))
  Running setup.py egg_info for package bcrypt
    OS/X: confusion between 'cc' versus 'gcc' (see issue 123)
    will not use '__thread' in the C code
    c/_cffi_backend.c:14:10: fatal error: 'ffi.h' file not found
    #include <ffi.h>
             ^
    1 error generated.
    Traceback (most recent call last):
      File "<string>", line 16, in <module>
      File "/Users/cody/virtualenvs/analytics/build/bcrypt/setup.py", line 104, in <module>
        "Programming Language :: Python :: 3.3",
      File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/core.py", line 112, in setup
        _setup_distribution = dist = klass(attrs)
      File "build/bdist.macosx-10.9-intel/egg/setuptools/dist.py", line 239, in __init__
      File "build/bdist.macosx-10.9-intel/egg/setuptools/dist.py", line 264, in fetch_build_eggs
      File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 620, in resolve
        dist = best[req.key] = env.best_match(req, ws, installer)
      File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 858, in best_match
        return self.obtain(req, installer) # try and download/install
      File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 870, in obtain
        return installer(requirement)
      File "build/bdist.macosx-10.9-intel/egg/setuptools/dist.py", line 314, in fetch_build_egg
      File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 593, in easy_install

      File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 623, in install_item

      File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 811, in install_eggs

      File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 1017, in build_and_install

      File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 1005, in run_setup

    distutils.errors.DistutilsError: Setup script exited with error: command 'cc' failed with exit status 1
    Complete output from command python setup.py egg_info:
    OS/X: confusion between 'cc' versus 'gcc' (see issue 123)

will not use '__thread' in the C code

c/_cffi_backend.c:14:10: fatal error: 'ffi.h' file not found

#include <ffi.h>

         ^

1 error generated.

Traceback (most recent call last):

  File "<string>", line 16, in <module>

  File "/Users/cody/virtualenvs/analytics/build/bcrypt/setup.py", line 104, in <module>

    "Programming Language :: Python :: 3.3",

  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/core.py", line 112, in setup

    _setup_distribution = dist = klass(attrs)

  File "build/bdist.macosx-10.9-intel/egg/setuptools/dist.py", line 239, in __init__

  File "build/bdist.macosx-10.9-intel/egg/setuptools/dist.py", line 264, in fetch_build_eggs

  File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 620, in resolve

    dist = best[req.key] = env.best_match(req, ws, installer)

  File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 858, in best_match

    return self.obtain(req, installer) # try and download/install

  File "build/bdist.macosx-10.9-intel/egg/pkg_resources.py", line 870, in obtain

    return installer(requirement)

  File "build/bdist.macosx-10.9-intel/egg/setuptools/dist.py", line 314, in fetch_build_egg

  File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 593, in easy_install



  File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 623, in install_item



  File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 811, in install_eggs



  File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 1017, in build_and_install



  File "build/bdist.macosx-10.9-intel/egg/setuptools/command/easy_install.py", line 1005, in run_setup



distutils.errors.DistutilsError: Setup script exited with error: command 'cc' failed with exit status 1

----------------------------------------
Command python setup.py egg_info failed with error code 1 in /Users/cody/virtualenvs/analytics/build/bcrypt

采纳答案by nathancahill

Without using sudo and CFLAGS and CPPFLAGS (unnecessary for pip):

不使用 sudo 和 CFLAGS 和 CPPFLAGS（pip 不需要）：

$ brew install pkg-config libffi
$ export PKG_CONFIG_PATH=/usr/local/Cellar/libffi/3.0.13/lib/pkgconfig/
$ pip install bcrypt

回答by Cody

I finally got it working with the following with a little help from theseposts:

我终于在这些帖子的帮助下完成了以下工作：

brew install pkg-config libffi
sudo bash
export CFLAGS=-Qunused-arguments
export CPPFLAGS=-Qunused-arguments
export PKG_CONFIG_PATH=/usr/local/Cellar/libffi/3.0.13/lib/pkgconfig/
pip install bcrypt

回答by Zach Young

Update 26/Aug/15

15 年 8 月 26 日更新

I think TA's answer is better in that it's handled by the system.

我认为 TA 的答案更好，因为它由系统处理。

---

---

First off, I'm loathe to install Brew or Ports, but that's another issue.

首先，我不愿意安装 Brew 或 Ports，但这是另一个问题。

I've been trying to pip install cryptography, which depends on cffi, which imports ffi.h.

我一直在尝试pip install cryptography，这取决于 cffi，它导入ffi.h.

I am curious why no one addressed that he (and me, and I believe others) have ffiinstalled with Xcode:

我很好奇为什么没有人提到他（和我，以及我相信其他人）已经ffi安装了 Xcode：

locate ffi.h
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/usr/include/ffi/ffi.h

since the error is specifically about "not finding" ffi.hwith the following build command:

因为该错误专门ffi.h与以下构建命令有关“未找到” ：

c/_cffi_backend.c:14:10: fatal error: 'ffi.h' file not found
#include <ffi.h>
...
...
/usr/bin/clang ...{omitted}... I/usr/include/ffi -I/usr/include/libffi

I have ffi.h, it's just that the system thinks it should be in /usr/include/....

我有ffi.h，只是系统认为它应该在/usr/include/....

My /usr/includedirectory happens to be empty, and not linked to anything, so I just linked the directory/file in question, to the place where it's not being found:

我的/usr/include目录恰好是空的，并且没有链接到任何东西，所以我只是将有问题的目录/文件链接到了找不到它的地方：

ln -fs {THAT_XCODE_SDK_FFI_PATH_FROM_ABOVE} /usr/include/ffi

I can now install and build cffi and cryptography.

我现在可以安装和构建 cffi 和密码学。

I'm very novice when it comes to understanding build-chain/linking dynamics, and if this is bad, I don't get it... so, please let me know.

在理解构建链/链接动态方面，我非常新手，如果这很糟糕，我不明白……所以，请告诉我。

回答by T A

Xcode was already installed for me (as mentioned in the question itself that it does provide the ffi.h header), but for some reason that didn't populate /usr/include (as Zachary Young mentioned). I dug around to see why the /usr/include wasn't populated and found that the following command fixed it:

Xcode 已经为我安装了（如问题本身所述，它确实提供了 ffi.h 标头），但由于某种原因没有填充 /usr/include （如 Zachary Young 提到的）。我四处寻找为什么没有填充 /usr/include 并发现以下命令修复了它：

$ xcode-select --install

Missing /usr/include after Yosemite and Xcode install?

在 Yosemite 和 Xcode 安装后缺少 /usr/include？