python - Snow Leopard、Homebrew python 2.7、virtualenv、libjpeg 和 PIL = 导入错误

Question

这个问题在 StackOverflow 和整个网络上有很多排列。我尝试了很多方法，但没有一个对我有用。

这是我的设置。我运行的是 OS X 10.6。我使用 Homebrew 安装 Python 2.7.1:

$ python
Python 2.7.1 (r271:86832, Mar 12 2011, 16:21:44) 
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin

请注意，在事件监视器中，这被报告为 64 位进程。

首先，我尝试使用 Homebrew 安装 libjpeg。后来我卸载了它并通过下载源代码将其安装到/usr/local，如下所示:

export CC="/usr/bin/gcc -arch x86_64"
./configure --enable-shared --enable-static
make
sudo make install

然后，在我的 Django virtualenv 中，我重新安装 PIL:

export CC="/usr/bin/gcc -arch x86_64"
pip uninstall PIL
pip install --no-install PIL
vi build/PIL/setup.py  # change JPEG_ROOT to libinclude("/usr/local")
pip install PIL

但仍然不起作用:

>>> import _imaging
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: dlopen(/Users/me/byp/lib/python2.7/site-packages/PIL/_imaging.so, 2): Symbol not found: _jpeg_resync_to_restart
  Referenced from: /Users/me/byp/lib/python2.7/site-packages/PIL/_imaging.so
  Expected in: dynamic lookup

Answer 1

byp 是你的 virtualenv 吗？我只是做了同样的事情，尽管使用的是Python 2.6系统并且没有任何问题。如果需要，您可以将 libjpeg 直接安装到 virtualenv 中，这样您就不必破解 PIL 构建脚本。这是我所做的:

% mkvirtualenv foo
(foo)% cdvirtualenv
(foo)% lftpget http://www.ijg.org/files/jpegsrc.v8c.tar.gz
(foo)% tar zxf jpegsrc.v8c.tar.gz
(foo)% cd jpeg-8c
(foo)% CC="gcc -arch x86_64" ./configure --prefix=$VIRTUAL_ENV
(foo)% make install
(foo)% cd ..
(foo)% pip install PIL
(foo)% python
Python 2.6.1 (r261:67515, Jun 24 2010, 21:47:49)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import _imaging
>>> _imaging
<module '_imaging' from '/Users/nicholas/LMI/foo/lib/python2.6/site-packages/PIL/_imaging.so'>
>>> ^D

虽然 _imaging.so 是为 i386、ppc 和 x86_64 构建的(因为 Apple 的 Python 就是这样构建的)已编译)，libjpeg 是为 x86_64 编译的，只是因为我给了 gcc 的标志:

(foo)% file lib/libjpeg.8.dylib
lib/libjpeg.8.dylib: Mach-O 64-bit dynamically linked shared library x86_64
(foo)% file lib/python2.6/site-packages/PIL/_imaging.so
lib/python2.6/site-packages/PIL/_imaging.so: Mach-O universal binary with 3 architectures
lib/python2.6/site-packages/PIL/_imaging.so (for architecture i386):    Mach-O bundle i386
lib/python2.6/site-packages/PIL/_imaging.so (for architecture ppc7400): Mach-O bundle ppc
lib/python2.6/site-packages/PIL/_imaging.so (for architecture x86_64):  Mach-O 64-bit bundle x86_64
(foo)% otool -L lib/python2.6/site-packages/PIL/_imaging.so
lib/python2.6/site-packages/PIL/_imaging.so:
    /Users/nicholas/LMI/foo/lib/libjpeg.8.dylib (compatibility version 12.0.0, current version 12.0.0)
    /opt/local/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.5)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.1)

因为 _imaging.so 动态链接到 libjpeg，所以如果 dylib 在预期架构中不可用，它会在加载时失败。我能够通过以 32 位运行 Python 来引发与您所看到的类似的结果:

(foo)% arch -i386 python
Python 2.6.1 (r261:67515, Jun 24 2010, 21:47:49)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import _imaging
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: dlopen(/Users/nicholas/LMI/foo/lib/python2.6/site-packages/PIL/_imaging.so, 2): Symbol not found: _jpeg_resync_to_restart
  Referenced from: /Users/nicholas/LMI/foo/lib/python2.6/site-packages/PIL/_imaging.so
  Expected in: flat namespace
 in /Users/nicholas/LMI/foo/lib/python2.6/site-packages/PIL/_imaging.so

所以我会检查Python、PIL和libjpeg的架构是否兼容。不过，您没有收到更好的错误消息，这很烦人!