title: Attempting to use gevent library in Python: "ImportError: cannot import name core"
body: <p>I'm attempting to use the <a href="http://code.google.com/p/gevent/" rel="nofollow noreferrer">gevent</a> library in a Python app I'm writing. However, both easy_install and installing it manually appears to be failing.  Any suggestions?</p>
  
  <pre><code>Python 2.6.2 (r262:71600, Aug  5 2009, 10:31:21) 
  [GCC 4.1.2 20080704 (Red Hat 4.1.2-44)] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import gevent
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "gevent/__init__.py", line 28, in &lt;module&gt;
      from gevent.greenlet import Greenlet, joinall, killall
    File "gevent/greenlet.py", line 5, in &lt;module&gt;
      from gevent import core
  ImportError: cannot import name core
  &gt;&gt;&gt; 
  </code></pre>
  
  <p>The complete dump of my "build" and "install" commands are:</p>
  
  <pre><code>(env)[root@test1:downloads/gevent-0.10.0]# python setup.py build                                        (02-20 16:00)
  found system libevent for linux2
  running build
  running build_py
  creating build/lib.linux-i686-2.6
  creating build/lib.linux-i686-2.6/gevent
  copying gevent/rawgreenlet.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/thread.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/greenlet.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/event.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/hub.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/util.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/monkey.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/__init__.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/coros.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/select.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/wsgi.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/socket.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/queue.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/pool.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/timeout.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/backdoor.py -&gt; build/lib.linux-i686-2.6/gevent
  copying gevent/proc.py -&gt; build/lib.linux-i686-2.6/gevent
  running build_ext
  building 'gevent.core' extension
  creating build/temp.linux-i686-2.6
  creating build/temp.linux-i686-2.6/gevent
  gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/usr/local/include/python2.6 -c gevent/core.c -o build/temp.linux-i686-2.6/gevent/core.o
  gevent/core.c: In function â€˜__pyx_pf_6gevent_4core_get_header_versionâ€™:
  gevent/core.c:4360: warning: label â€˜__pyx_L1_errorâ€™ defined but not used
  gevent/core.c: In function â€˜__pyx_pf_6gevent_4core_reinitâ€™:
  gevent/core.c:4419: warning: label â€˜__pyx_L1_errorâ€™ defined but not used
  gcc -pthread -shared build/temp.linux-i686-2.6/gevent/core.o -levent -o build/lib.linux-i686-2.6/gevent/core.so
  (env)[root@test1:downloads/gevent-0.10.0]# python setup.py install                                      (02-20 16:01)
  found system libevent for linux2
  running install
  running build
  running build_py
  running build_ext
  running install_lib
  creating /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/rawgreenlet.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/thread.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/greenlet.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/event.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/hub.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/util.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/monkey.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/__init__.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/coros.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/select.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/wsgi.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/socket.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/queue.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/pool.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/timeout.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/backdoor.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/proc.py -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  copying build/lib.linux-i686-2.6/gevent/core.so -&gt; /ews/test_project/env/lib/python2.6/site-packages/gevent
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/rawgreenlet.py to rawgreenlet.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/thread.py to thread.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/greenlet.py to greenlet.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/event.py to event.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/hub.py to hub.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/util.py to util.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/monkey.py to monkey.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/__init__.py to __init__.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/coros.py to coros.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/select.py to select.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/wsgi.py to wsgi.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/socket.py to socket.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/queue.py to queue.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/pool.py to pool.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/timeout.py to timeout.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/backdoor.py to backdoor.pyc
  byte-compiling /ews/test_project/env/lib/python2.6/site-packages/gevent/proc.py to proc.pyc
  running install_egg_info
  Writing /ews/test_project/env/lib/python2.6/site-packages/gevent-0.10.0-py2.6.egg-info
  (env)[root@test1:downloads/gevent-0.10.0]# python                                                       (02-20 16:01)
  Python 2.6.2 (r262:71600, Aug  5 2009, 10:31:21) 
  [GCC 4.1.2 20080704 (Red Hat 4.1.2-44)] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import gevent
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "gevent/__init__.py", line 28, in &lt;module&gt;
      from gevent.greenlet import Greenlet, joinall, killall
    File "gevent/greenlet.py", line 5, in &lt;module&gt;
      from gevent import core
  ImportError: cannot import name core
  &gt;&gt;&gt; 
  </code></pre>