Why I'm getting this error while building docker image?

Question:

I got the following error while building a docker image by "docker-compose build".

ERROR: Couldn't connect to Docker daemon at http://127.0.0.1:2375 - is it running?

If it's at a non-standard location, specify the URL with the DOCKER_HOST environment variable.

Even if I try with "sudo", I got this:

Building web
Step 1/8 : FROM python:3.8.3-alpine
 ---> 8ecf5a48c789
Step 2/8 : WORKDIR /usr/src/app
 ---> Using cache
 ---> 87bb0088a0ba
Step 3/8 : ENV PYTHONDONTWRITEBYTECODE 1
 ---> Using cache
 ---> 4f1a6ddf9e1f
Step 4/8 : ENV PYTHONUNBUFFERED 1
 ---> Using cache
 ---> 5d22b6b7a0f5
Step 5/8 : RUN pip install --upgrade pip
 ---> Using cache
 ---> 169ee831f728
Step 6/8 : COPY ./requirements.txt .
 ---> Using cache
 ---> 4b4351e31632
Step 7/8 : RUN pip install -r requirements.txt
 ---> Running in a4dae2fe3761
Collecting asgiref==3.2.10
  Downloading asgiref-3.2.10-py3-none-any.whl (19 kB)
Collecting cffi==1.14.3
  Downloading cffi-1.14.3.tar.gz (470 kB)
Collecting cryptography==3.2.1
  Downloading cryptography-3.2.1.tar.gz (540 kB)
  Installing build dependencies: started
  Installing build dependencies: finished with status 'error'
  ERROR: Command errored out with exit status 1:
   command: /usr/local/bin/python /usr/local/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-p3ocmpkd/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'setuptools>=40.6.0' wheel 'cffi>=1.8,!=1.11.3; platform_python_implementation != '"'"'PyPy'"'"''
       cwd: None
  Complete output (128 lines):
  Collecting setuptools>=40.6.0
    Downloading setuptools-50.3.2-py3-none-any.whl (785 kB)
  Collecting wheel
    Downloading wheel-0.35.1-py2.py3-none-any.whl (33 kB)
  Collecting cffi!=1.11.3,>=1.8
    Using cached cffi-1.14.3.tar.gz (470 kB)
  Collecting pycparser
    Downloading pycparser-2.20-py2.py3-none-any.whl (112 kB)
  Building wheels for collected packages: cffi
    Building wheel for cffi (setup.py): started
    Building wheel for cffi (setup.py): finished with status 'error'
    ERROR: Command errored out with exit status 1:
     command: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-_eoslhz1/cffi/setup.py'"'"'; __file__='"'"'/tmp/pip-install-_eoslhz1/cffi/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'rn'"'"', '"'"'n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-99ngzpxw
         cwd: /tmp/pip-install-_eoslhz1/cffi/
    Complete output (50 lines):
    unable to execute 'gcc': No such file or directory
    unable to execute 'gcc': No such file or directory
  
        No working compiler found, or bogus compiler options passed to
        the compiler from Python's standard "distutils" module.  See
        the error messages above.  Likely, the problem is not related
        to CFFI but generic to the setup.py of any Python package that
        tries to compile C code.  (Hints: on OS/X 10.8, for errors about
        -mno-fused-madd see http://stackoverflow.com/questions/22313407/
        Otherwise, see https://wiki.python.org/moin/CompLangPython or
        the IRC channel #python on irc.freenode.net.)
  
        Trying to continue anyway.  If you are trying to install CFFI from
        a build done in a different context, you can ignore this warning.
  
    running bdist_wheel
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-3.8
    creating build/lib.linux-x86_64-3.8/cffi
    copying cffi/api.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/verifier.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/recompiler.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/vengine_gen.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/model.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/__init__.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/error.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/ffiplatform.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/cparser.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/backend_ctypes.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/cffi_opcode.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/commontypes.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/pkgconfig.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/setuptools_ext.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/lock.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/vengine_cpy.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/_cffi_include.h -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/parse_c_type.h -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/_embedding.h -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/_cffi_errors.h -> build/lib.linux-x86_64-3.8/cffi
    warning: build_py: byte-compiling is disabled, skipping.
  
    running build_ext
    building '_cffi_backend' extension
    creating build/temp.linux-x86_64-3.8
    creating build/temp.linux-x86_64-3.8/c
    gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DTHREAD_STACK_SIZE=0x100000 -fPIC -I/usr/include/ffi -I/usr/include/libffi -I/usr/local/include/python3.8 -c c/_cffi_backend.c -o build/temp.linux-x86_64-3.8/c/_cffi_backend.o
    unable to execute 'gcc': No such file or directory
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
    ERROR: Failed building wheel for cffi
    Running setup.py clean for cffi
  Failed to build cffi
  Installing collected packages: setuptools, wheel, pycparser, cffi
      Running setup.py install for cffi: started
      Running setup.py install for cffi: finished with status 'error'
      ERROR: Command errored out with exit status 1:
       command: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-_eoslhz1/cffi/setup.py'"'"'; __file__='"'"'/tmp/pip-install-_eoslhz1/cffi/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'rn'"'"', '"'"'n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-pah2aui6/install-record.txt --single-version-externally-managed --prefix /tmp/pip-build-env-p3ocmpkd/overlay --compile --install-headers /tmp/pip-build-env-p3ocmpkd/overlay/include/python3.8/cffi
           cwd: /tmp/pip-install-_eoslhz1/cffi/
      Complete output (50 lines):
      unable to execute 'gcc': No such file or directory
      unable to execute 'gcc': No such file or directory
  
          No working compiler found, or bogus compiler options passed to
          the compiler from Python's standard "distutils" module.  See
          the error messages above.  Likely, the problem is not related
          to CFFI but generic to the setup.py of any Python package that
          tries to compile C code.  (Hints: on OS/X 10.8, for errors about
          -mno-fused-madd see http://stackoverflow.com/questions/22313407/
          Otherwise, see https://wiki.python.org/moin/CompLangPython or
          the IRC channel #python on irc.freenode.net.)
  
          Trying to continue anyway.  If you are trying to install CFFI from
          a build done in a different context, you can ignore this warning.
  
      running install
      running build
      running build_py
      creating build
      creating build/lib.linux-x86_64-3.8
      creating build/lib.linux-x86_64-3.8/cffi
      copying cffi/api.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/verifier.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/recompiler.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/vengine_gen.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/model.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/__init__.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/error.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/ffiplatform.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/cparser.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/backend_ctypes.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/cffi_opcode.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/commontypes.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/pkgconfig.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/setuptools_ext.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/lock.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/vengine_cpy.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/_cffi_include.h -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/parse_c_type.h -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/_embedding.h -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/_cffi_errors.h -> build/lib.linux-x86_64-3.8/cffi
      warning: build_py: byte-compiling is disabled, skipping.
  
      running build_ext
      building '_cffi_backend' extension
      creating build/temp.linux-x86_64-3.8
      creating build/temp.linux-x86_64-3.8/c
      gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DTHREAD_STACK_SIZE=0x100000 -fPIC -I/usr/include/ffi -I/usr/include/libffi -I/usr/local/include/python3.8 -c c/_cffi_backend.c -o build/temp.linux-x86_64-3.8/c/_cffi_backend.o
      unable to execute 'gcc': No such file or directory
      error: command 'gcc' failed with exit status 1
      ----------------------------------------
  ERROR: Command errored out with exit status 1: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-_eoslhz1/cffi/setup.py'"'"'; __file__='"'"'/tmp/pip-install-_eoslhz1/cffi/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'rn'"'"', '"'"'n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-pah2aui6/install-record.txt --single-version-externally-managed --prefix /tmp/pip-build-env-p3ocmpkd/overlay --compile --install-headers /tmp/pip-build-env-p3ocmpkd/overlay/include/python3.8/cffi Check the logs for full command output.
  ----------------------------------------
ERROR: Command errored out with exit status 1: /usr/local/bin/python /usr/local/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-p3ocmpkd/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'setuptools>=40.6.0' wheel 'cffi>=1.8,!=1.11.3; platform_python_implementation != '"'"'PyPy'"'"'' Check the logs for full command output.
ERROR: Service 'web' failed to build: The command '/bin/sh -c pip install -r requirements.txt' returned a non-zero code: 1

That is my Dockerfile:

# pull official base image
FROM python:3.8.3-alpine

# set work directory
WORKDIR /usr/src/app

# set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1

# install dependencies
RUN pip install --upgrade pip
COPY ./requirements.txt .
RUN pip install -r requirements.txt

# copy project
COPY . .

and docker-compose.yml:

version: '3.7'

services:
  web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - ./:/usr/src/app/
    ports:
      - 8000:8000
    env_file:
      - ./.env.dev

I will add that I bought my laptop a few months ago, and already had problems with Docker on my previous system on this device (that’s one of the reasons I changed my system). I switched from Fedora to Ubuntu.

Additionally, there is no "python" alias for python3 in my shell, and because of the unknown reason I need to put "python3 -m" before simple "pip freeze".

I hope that information may be useful.
Thank You.

.
.
.

After adding a "RUN apk add builder-base" in my Dockerfile, following error appears:

Step 8/9 : RUN pip install -r requirements.txt
 ---> Running in cd9c74fbd831
Collecting asgiref==3.2.10
  Downloading asgiref-3.2.10-py3-none-any.whl (19 kB)
Collecting cffi==1.14.3
  Downloading cffi-1.14.3.tar.gz (470 kB)
Collecting cryptography==3.2.1
  Downloading cryptography-3.2.1.tar.gz (540 kB)
  Installing build dependencies: started
  Installing build dependencies: finished with status 'error'
  ERROR: Command errored out with exit status 1:
   command: /usr/local/bin/python /usr/local/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-gbfaltlj/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'setuptools>=40.6.0' wheel 'cffi>=1.8,!=1.11.3; platform_python_implementation != '"'"'PyPy'"'"''
       cwd: None
  Complete output (104 lines):
  Collecting setuptools>=40.6.0
    Downloading setuptools-50.3.2-py3-none-any.whl (785 kB)
  Collecting wheel
    Downloading wheel-0.35.1-py2.py3-none-any.whl (33 kB)
  Collecting cffi!=1.11.3,>=1.8
    Using cached cffi-1.14.3.tar.gz (470 kB)
  Collecting pycparser
    Downloading pycparser-2.20-py2.py3-none-any.whl (112 kB)
  Building wheels for collected packages: cffi
    Building wheel for cffi (setup.py): started
    Building wheel for cffi (setup.py): finished with status 'error'
    ERROR: Command errored out with exit status 1:
     command: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-myhajkmm/cffi/setup.py'"'"'; __file__='"'"'/tmp/pip-install-myhajkmm/cffi/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'rn'"'"', '"'"'n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-9jsg5veu
         cwd: /tmp/pip-install-myhajkmm/cffi/
    Complete output (38 lines):
    running bdist_wheel
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-3.8
    creating build/lib.linux-x86_64-3.8/cffi
    copying cffi/api.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/verifier.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/recompiler.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/vengine_gen.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/model.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/__init__.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/error.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/ffiplatform.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/cparser.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/backend_ctypes.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/cffi_opcode.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/commontypes.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/pkgconfig.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/setuptools_ext.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/lock.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/vengine_cpy.py -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/_cffi_include.h -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/parse_c_type.h -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/_embedding.h -> build/lib.linux-x86_64-3.8/cffi
    copying cffi/_cffi_errors.h -> build/lib.linux-x86_64-3.8/cffi
    warning: build_py: byte-compiling is disabled, skipping.
  
    running build_ext
    building '_cffi_backend' extension
    creating build/temp.linux-x86_64-3.8
    creating build/temp.linux-x86_64-3.8/c
    gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DTHREAD_STACK_SIZE=0x100000 -fPIC -DUSE__THREAD -DHAVE_SYNC_SYNCHRONIZE -I/usr/include/ffi -I/usr/include/libffi -I/usr/local/include/python3.8 -c c/_cffi_backend.c -o build/temp.linux-x86_64-3.8/c/_cffi_backend.o
    c/_cffi_backend.c:15:10: fatal error: ffi.h: No such file or directory
       15 | #include <ffi.h>
          |          ^~~~~~~
    compilation terminated.
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
    ERROR: Failed building wheel for cffi
    Running setup.py clean for cffi
  Failed to build cffi
  Installing collected packages: setuptools, wheel, pycparser, cffi
      Running setup.py install for cffi: started
      Running setup.py install for cffi: finished with status 'error'
      ERROR: Command errored out with exit status 1:
       command: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-myhajkmm/cffi/setup.py'"'"'; __file__='"'"'/tmp/pip-install-myhajkmm/cffi/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'rn'"'"', '"'"'n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-s86a1yn7/install-record.txt --single-version-externally-managed --prefix /tmp/pip-build-env-gbfaltlj/overlay --compile --install-headers /tmp/pip-build-env-gbfaltlj/overlay/include/python3.8/cffi
           cwd: /tmp/pip-install-myhajkmm/cffi/
      Complete output (38 lines):
      running install
      running build
      running build_py
      creating build
      creating build/lib.linux-x86_64-3.8
      creating build/lib.linux-x86_64-3.8/cffi
      copying cffi/api.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/verifier.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/recompiler.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/vengine_gen.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/model.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/__init__.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/error.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/ffiplatform.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/cparser.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/backend_ctypes.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/cffi_opcode.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/commontypes.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/pkgconfig.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/setuptools_ext.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/lock.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/vengine_cpy.py -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/_cffi_include.h -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/parse_c_type.h -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/_embedding.h -> build/lib.linux-x86_64-3.8/cffi
      copying cffi/_cffi_errors.h -> build/lib.linux-x86_64-3.8/cffi
      warning: build_py: byte-compiling is disabled, skipping.
  
      running build_ext
      building '_cffi_backend' extension
      creating build/temp.linux-x86_64-3.8
      creating build/temp.linux-x86_64-3.8/c
      gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DTHREAD_STACK_SIZE=0x100000 -fPIC -DUSE__THREAD -DHAVE_SYNC_SYNCHRONIZE -I/usr/include/ffi -I/usr/include/libffi -I/usr/local/include/python3.8 -c c/_cffi_backend.c -o build/temp.linux-x86_64-3.8/c/_cffi_backend.o
      c/_cffi_backend.c:15:10: fatal error: ffi.h: No such file or directory
         15 | #include <ffi.h>
            |          ^~~~~~~
      compilation terminated.
      error: command 'gcc' failed with exit status 1
      ----------------------------------------
  ERROR: Command errored out with exit status 1: /usr/local/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-myhajkmm/cffi/setup.py'"'"'; __file__='"'"'/tmp/pip-install-myhajkmm/cffi/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'rn'"'"', '"'"'n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-s86a1yn7/install-record.txt --single-version-externally-managed --prefix /tmp/pip-build-env-gbfaltlj/overlay --compile --install-headers /tmp/pip-build-env-gbfaltlj/overlay/include/python3.8/cffi Check the logs for full command output.
  ----------------------------------------
ERROR: Command errored out with exit status 1: /usr/local/bin/python /usr/local/lib/python3.8/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-gbfaltlj/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- 'setuptools>=40.6.0' wheel 'cffi>=1.8,!=1.11.3; platform_python_implementation != '"'"'PyPy'"'"'' Check the logs for full command output.
ERROR: Service 'web' failed to build: The command '/bin/sh -c pip install -r requirements.txt' returned a non-zero code: 1

Asked By: Przemek Baj

||

Answers:

Alpine Linux does not support the binary wheels Python packages ship under the manylinux tag, so you have to compile things like cffi and cryptography yourself. To do so you’ll need a compiler and the correct set of headers. This is documented in the cryptography installation documentation for Alpine.

Update September 2021: There is now a musllinux standard which allows binary wheels that work with Alpine. To use them you must have pip 21.2.4 or greater.

Answered By: Paul Kehrer

in your dockerfile you can use a base image that has more libraries for compiling the dependencies

# pull official base image
FROM python:3.8

this should allow you to compile the app

Answered By: Harry Moreno
Categories: questions Tags: , ,
Answers are sorted by their score. The answer accepted by the question owner as the best is marked with
at the top-right corner.