Mein Ubuntu ist 14.04 LTS.
Wenn ich Kryptografie installiere, ist der Fehler:
Installing egg-scripts.
uses namespace packages but the distribution does not require setuptools.
Getting distribution for 'cryptography==0.2.1'.
no previously-included directories found matching 'documentation/_build'
zip_safe flag not set; analyzing archive contents...
six: module references __path__
Installed /tmp/easy_install-oUz7ei/cryptography-0.2.1/.eggs/six-1.10.0-py2.7.egg
Searching for cffi>=0.8
Reading https://pypi.python.org/simple/cffi/
Best match: cffi 1.5.0
Downloading https://pypi.python.org/packages/source/c/cffi/cffi-1.5.0.tar.gz#md5=dec8441e67880494ee881305059af656
Processing cffi-1.5.0.tar.gz
Writing /tmp/easy_install-oUz7ei/cryptography-0.2.1/temp/easy_install-Yf2Yl3/cffi-1.5.0/setup.cfg
Running cffi-1.5.0/setup.py -q bdist_egg --dist-dir /tmp/easy_install-oUz7ei/cryptography-0.2.1/temp/easy_install-Yf2Yl3/cffi-1.5.0/egg-dist-tmp-A2kjMD
c/_cffi_backend.c:15:17: fatal error: ffi.h: No such file or directory
#include <ffi.h>
^
compilation terminated.
error: Setup script exited with error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
An error occurred when trying to install cryptography 0.2.1. Look above this message for any errors that were output by easy_install.
While:
Installing egg-scripts.
Getting distribution for 'cryptography==0.2.1'.
Error: Couldn't install: cryptography 0.2.1
Ich weiß nicht, warum es fehlgeschlagen ist. Was ist der Grund. Ist bei der Installation auf dem Ubuntu-System etwas erforderlich?