CPython

For more complete instructions on contributing to CPython development, see the Developer Guide . Installable Python kits, and information about using Python, are available at python.org . You can pass many options to the configure script; run ./configure --help to find out more. On macOS case-insensitive file systems and on Cygwin, the executable is called python.exe ; elsewhere it's just python . Building a complete Python installation requires the use of various additional third-party libraries, depending on your build platform and configure options. Not all standard library modules are buildable or usable on all platforms. Refer to the Install dependencies section of the Developer Guide for current detailed information on dependencies for various Linux distributions and macOS. On macOS, there are additional configure and build options related to macOS framework and universal builds. Refer to Mac/README.rst . If you wish, you can create a subdirectory and invoke configure from there. For example:: (This will fail if you also built at the top-level directory. You should do a make clean at the top-level first.) To get an optimized build of Python, configure --enable-optimizations before you run make . This sets the default make targets up to enable Profile Guided Optimization (PGO) and may be used to auto-enable Link Time Optimization (LTO) on some platforms. For more details, see the sections below. PGO takes advantage of recent versions of the GCC or Clang compilers. If used, either via configure --enable-optimizations or by manually running make profile-opt regardless of configure flags, the optimized build process will perform the following steps: The entire Python directory is cleaned of temporary files that may have resulted from a previous compilation. An instrumented version of the interpreter is built, using suitable compiler flags for each flavor. Note that this is just an intermediary step. The binary resulting from this step is not good for real-life workloads as it has profiling instructions embedded inside. After the instrumented interpreter is built, the Makefile will run a training workload. This is necessary in order to profile the interpreter's execution. Note also that any output, both stdout and stderr, that may appear at this step is suppressed. The final step is to build the actual interpreter, using the information collected from the instrumented one. The end result will be a Python binary that is optimized; suitable for distribution or production installation. Enabled via configure's --with-lto flag. LTO takes advantage of the ability of recent compiler toolchains to optimize across the otherwise arbitrary .o file boundary when building final executables or shared libraries for additional performance gains. If you want to install multiple versions of Python, see the section below entitled "Installing multiple versions". It can also be downloaded in many formats for faster access. The documentation is downloadable in HTML, EPUB, and reStructuredText formats; the latter version is primarily for documentation authors, translators, and people with special formatting requirements. To test the interpreter, type make test in the top-level directory. The test set produces some output. You can generally ignore the messages about skipped tests due to optional features which can't be imported. If a message is printed about a failed test or a traceback or core dump is produced, something is wrong. By default, tests are prevented from overusing resources like disk space and memory. To enable these tests, run make buildbottest . If any tests fail, you can re-run the failing test(s) in verbose mode. For example, if test os and test gdb failed, you can run:: If the failure persists and appears to be a problem with Python rather than your environment, you can file a bug report and include relevant output from that command to show the issue. On Unix and Mac systems if you intend to install multiple ve