Beyond Linux® From Scratch (systemd edition) - Version 8.4

Chapter 13. Programming

Python-3.7.2

Introduction to Python 3

The Python 3 package contains the Python development environment. This is useful for object-oriented programming, writing scripts, prototyping large programs or developing entire applications.

[Note]

Note

Python 3 was installed in LFS. The only reason to rebuild it here is if optional modules are needed.

This package is known to build and work properly using an LFS-8.4 platform.

Package Information

Python 3 Dependencies

Optional

BlueZ-5.50, GDB-8.2.1 (required for some tests), Valgrind-3.14.0, and libmpcdec

Optional (For Additional Modules)

Berkeley DB-5.3.28 and SQLite-3.27.1

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/Python3

Installation of Python 3

Install Python 3 by running the following commands: 

CXX="/usr/bin/g++"              \
./configure --prefix=/usr       \
            --enable-shared     \
            --with-system-expat \
            --with-system-ffi   \
            --with-ensurepip=yes &&
make

The test suite must be run separately, using an X terminal (see below).

Now, as the root user: 

make install &&
chmod -v 755 /usr/lib/libpython3.7m.so &&
chmod -v 755 /usr/lib/libpython3.so

The test suite must be run separately from the build, either before or after the package is built and installed. Do not run make install after running the test suite. To build and install the package, you need to start with a fresh or clean source tree. For the tests, you also need a clean source code, so either start by removing the source code directory and starting over, by uncompressing the source tarball or by running make clean. Then configure again, adding “--with-pydebug” to the configure switches above, run make, then make test. Remember that tests must be executed using an X terminal. Two tests fail. The test SBU highly depends on the speed of the internet connection.

Command Explanations

CXX="/usr/bin/g++" ./configure ...: Avoid an annoying message during configuration.

--with-system-expat: This switch enables linking against the system version of Expat.

--with-system-ffi: This switch enables linking against system version of libffi.

--with-ensurepip=yes : This switch enables building pip and setuptools packaging programs. setuptools is needed for building some Python modules.

--with-dbmliborder=bdb:gdbm:ndbm: Use this switch if you want to build Python DBM Module against Berkeley DB instead of GDBM.

chmod ...: Fix permissions for shared libraries to be consistent with other libraries.

Configuring Python 3

In order for python3 to find the installed documentation, create the following version independent symlink: 

ln -svfn python-3.7.2 /usr/share/doc/python-3

and add the following environment variable to the individual user's or system's profile: 

export PYTHONDOCS=/usr/share/doc/python-3/html

Contents

Installed Programs: 2to3 (symlink), 2to3-3.7, idle3 (symlink), and idle3.7 pydoc3 (symlink), pydoc3.7, python3 (symlink); python3.7 and python3.7m (hardlinked); python3-config (symlink), python3.7-config (symlink), python3.7m-config, pyvenv (symlink), pyvenv-3.7,
Installed Libraries: libpython3.7m.so and libpython3.so
Installed Directories: /usr/include/python3.7m, /usr/lib/python3.7, and /usr/share/doc/python-3.7.2

Short Descriptions

idle3

is a wrapper script that opens a Python aware GUI editor. For this script to run, you must have installed Tk before Python so that the Tkinter Python module is built.

pydoc3

is the Python documentation tool.

python3

is an interpreted, interactive, object-oriented programming language.

python3.7

is a version-specific name for the python program.

pyvenv

creates virtual Python environments in one or more target directories.

Last updated on 2019-02-15 18:50:09 -0800