cpython/PCbuild

Building Python using Microsoft Visual C++

------------------------------------------



This directory is used to build CPython for Microsoft Windows NT version

5.1 or higher (Windows XP, Windows Server 2003, or later) on 32 and 64

bit platforms.  Using this directory requires an installation of

Microsoft Visual C++ 2010 (MSVC 10.0) of any edition.  The specific

requirements are as follows:



Visual C++ 2010 Express Edition

    Required for building 32-bit Debug and Release configuration builds.

    The Python build solution pcbuild.sln makes use of Solution Folders,

    which this edition does not support.  Any time pcbuild.sln is opened

    or reloaded by Visual C++, a warning about Solution Folders will be

    displayed which can be safely dismissed with no impact on your

    ability to build Python.

Visual Studio 2010 Professional Edition

    Required for building 64-bit Debug and Release configuration builds

Visual Studio 2010 Premium Edition

    Required for building Release configuration builds that make use of

    Profile Guided Optimization (PGO), on either platform.



Installing Service Pack 1 for Visual Studio 2010 is highly recommended

to avoid LNK1123 errors.



All you need to do to build is open the solution "pcbuild.sln" in Visual

Studio, select the desired combination of configuration and platform,

then build with "Build Solution" or the F7 keyboard shortcut.  You can

also build from the command line using the "build.bat" script in this

directory.  The solution is configured to build the projects in the

correct order.



The solution currently supports two platforms.  The Win32 platform is

used to build standard x86-compatible 32-bit binaries, output into this

directory.  The x64 platform is used for building 64-bit AMD64 (aka

x86_64 or EM64T) binaries, output into the amd64 sub-directory which

will be created if it doesn't already exist.  The Itanium (IA-64)

platform is no longer supported.  See the "Building for AMD64" section

below for more information about 64-bit builds.



Four configuration options are supported by the solution:

Debug

    Used to build Python with extra debugging capabilities, equivalent

    to using ./configure --with-pydebug on UNIX.  All binaries built

    using this configuration have "_d" added to their name:

    python34_d.dll, python_d.exe, parser_d.pyd, and so on.  Both the

    build and rt (run test) batch files in this directory accept a -d

    option for debug builds.  If you are building Python to help with

    development of CPython, you will most likely use this configuration.

PGInstrument, PGUpdate

    Used to build Python in Release configuration using PGO, which

    requires Premium Edition of Visual Studio.  See the "Profile

    Guided Optimization" section below for more information.  Build

    output from each of these configurations lands in its own

    sub-directory of this directory.  The official Python releases are

    built using these configurations.

Release

    Used to build Python as it is meant to be used in production

    settings, though without PGO.





Legacy support

--------------



You can find build directories for older versions of Visual Studio and

Visual C++ in the PC directory. The legacy build directories are no

longer actively maintained and may not work out of the box.



Currently, the only legacy build directory is PC\VS9.0, for Visual

Studio 2008 (9.0).





C Runtime

---------



Visual Studio 2010 uses version 10 of the C runtime (MSVCRT10).  The

executables no longer use the "Side by Side" assemblies used in previous

versions of the compiler.  This simplifies distribution of applications.



The run time libraries are available under the VC/Redist folder of your

Visual Studio distribution. For more info, see the Readme in the

VC/Redist folder.





Sub-Projects

------------



The CPython project is split up into several smaller sub-projects which

are managed by the pcbuild.sln solution file.  Each sub-project is

represented by a .vcxproj and a .vcxproj.filters file starting with the

name of the sub-project.  These sub-projects fall into a few general

categories:



The following sub-projects represent the bare minimum required to build

a functioning CPython interpreter.  If nothing else builds but these,

you'll have a very limited but usable python.exe:

pythoncore

    .dll and .lib

python

    .exe

kill_python

    kill_python.exe, a small program designed to kill any instances of

    python(_d).exe that are running and live in the build output

    directory; this is meant to avoid build issues due to locked files

make_buildinfo, make_versioninfo

    helpers to provide necessary information to the build process



These sub-projects provide extra executables that are useful for running

CPython in different ways:

pythonw

    pythonw.exe, a variant of python.exe that doesn't open a Command

    Prompt window

pylauncher

    py.exe, the Python Launcher for Windows, see

        http://docs.python.org/3/using/windows.html#launcher

pywlauncher

    pyw.exe, a variant of py.exe that doesn't open a Command Prompt

    window

_testembed

    _testembed.exe, a small program that embeds Python for testing

    purposes, used by test_capi.py



These are miscellaneous sub-projects that don't really fit the other

categories.  By default, these projects do not build in Debug

configuration:

_freeze_importlib

    _freeze_importlib.exe, used to regenerate Python\importlib.h after

    changes have been made to Lib\importlib\_bootstrap.py

bdist_wininst

    ..\Lib\distutils\command\wininst-10.0[-amd64].exe, the base

    executable used by the distutils bdist_wininst command

python3dll

    python3.dll, the PEP 384 Stable ABI dll

xxlimited

    builds an example module that makes use of the PEP 384 Stable ABI,

    see Modules\xxlimited.c



The following sub-projects are for individual modules of the standard

library which are implemented in C; each one builds a DLL (renamed to

.pyd) of the same name as the project:

_ctypes

_ctypes_test

_decimal

_elementtree

_hashlib

_msi

_multiprocessing

_overlapped

_socket

_testcapi

_testbuffer

_testimportmultiple

pyexpat

select

unicodedata

winsound



The following Python-controlled sub-projects wrap external projects.

Note that these external libraries are not necessary for a working

interpreter, but they do implement several major features.  See the

"Getting External Sources" section below for additional information

about getting the source for building these libraries.  The sub-projects

are:

_bz2

    Python wrapper for version 1.0.6 of the libbzip2 compression library

    Homepage:

        http://www.bzip.org/

_lzma

    Python wrapper for the liblzma compression library, using pre-built

    binaries of XZ Utils version 5.0.5

    Homepage:

        http://tukaani.org/xz/

_ssl

    Python wrapper for version 1.0.2a of the OpenSSL secure sockets

    library, which is built by ssl.vcxproj

    Homepage:

        http://www.openssl.org/



    Building OpenSSL requires nasm.exe (the Netwide Assembler), version

    2.10 or newer from

        http://www.nasm.us/

    to be somewhere on your PATH.  More recent versions of OpenSSL may

    need a later version of NASM. If OpenSSL's self tests don't pass,

    you should first try to update NASM and do a full rebuild of

    OpenSSL.  If you use the Tools\buildbot\external(-amd64).bat method

    for getting sources, it also downloads a version of NASM which the

    ssl build script will add to PATH.



    If you like to use the official sources instead of the files from

    python.org's subversion repository, Perl is required to build the

    necessary makefiles and assembly files.  ActivePerl is available

    from

        http://www.activestate.com/activeperl/

    The svn.python.org version contains pre-built makefiles and assembly

    files.



    The build process makes sure that no patented algorithms are

    included.  For now RC5, MDC2 and IDEA are excluded from the build.

    You may have to manually remove $(OBJ_D)\i_*.obj from ms\nt.mak if

    using official sources; the svn.python.org-hosted version is already

    fixed.



    The ssl.vcxproj sub-project simply invokes PCbuild/build_ssl.py,

    which locates and builds OpenSSL.



    build_ssl.py attempts to catch the most common errors (such as not

    being able to find OpenSSL sources, or not being able to find a Perl

    that works with OpenSSL) and give a reasonable error message.  If

    you have a problem that doesn't seem to be handled correctly (e.g.,

    you know you have ActivePerl but we can't find it), please take a

    peek at build_ssl.py and suggest patches.  Note that build_ssl.py

    should be able to be run directly from the command-line.



    The ssl sub-project does not have the ability to clean the OpenSSL

    build; if you need to rebuild, you'll have to clean it by hand.

_sqlite3

    Wraps SQLite 3.8.3.1, which is itself built by sqlite3.vcxproj

    Homepage:

        http://www.sqlite.org/

_tkinter

    Wraps version 8.6.1 of the Tk windowing system.

    Homepage:

        http://www.tcl.tk/



    Unlike the other external libraries listed above, Tk must be built

    separately before the _tkinter module can be built. This means that

    a pre-built Tcl/Tk installation is expected in ..\externals\tcltk

    (tcltk64 for 64-bit) relative to this directory.  See "Getting

    External Sources" below for the easiest method to ensure Tcl/Tk is

    built.





Getting External Sources

------------------------



The last category of sub-projects listed above wrap external projects

Python doesn't control, and as such a little more work is required in

order to download the relevant source files for each project before they

can be built.  The buildbots must ensure that all libraries are present

before building, so the easiest approach is to run either external.bat

or external-amd64.bat (depending on platform) in the ..\Tools\buildbot

directory from ..\, i.e.:



    C:\python\cpython\PCbuild>cd ..

    C:\python\cpython>Tools\buildbot\external.bat



This extracts all the external sub-projects from

    http://svn.python.org/projects/external

via Subversion (so you'll need an svn.exe on your PATH) and places them

in ..\externals (relative to this directory).



It is also possible to download sources from each project's homepage,

though you may have to change the names of some folders in order to make

things work.  For instance, if you were to download a version 5.0.7 of

XZ Utils, you would need to extract the archive into ..\externals\xz-5.0.5

anyway, since that is where the solution is set to look for xz.  The

same is true for all other external projects.



The external(-amd64).bat scripts will also build a debug build of

Tcl/Tk, but there aren't any equivalent batch files for building release

versions of Tcl/Tk currently available.  If you need to build a release

version of Tcl/Tk, just take a look at the relevant external(-amd64).bat

file and find the two nmake lines, then call each one without the

'DEBUG=1' parameter, i.e.:



The external-amd64.bat file contains this for tcl:

    nmake -f makefile.vc DEBUG=1 MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 clean all install



So for a release build, you'd call it as:

    nmake -f makefile.vc MACHINE=AMD64 INSTALLDIR=..\..\tcltk64 clean all install



Note that the above command is called from within ..\externals\tcl-8.6.1.0\win

(relative to this directory); don't forget to build Tk as well as Tcl!



This will be cleaned up in the future; http://bugs.python.org/issue15968

tracks adding a new tcltk.vcxproj file that will build Tcl/Tk and Tix

the same way the other external projects listed above are built.





Building for AMD64

------------------



The build process for AMD64 / x64 is very similar to standard builds,

you just have to set x64 as platform. In addition, the HOST_PYTHON

environment variable must point to a Python interpreter (at least 2.4),

to support cross-compilation from Win32.  Note that Visual Studio

requires Professional Edition or better in order to build 64-bit

binaries.





Profile Guided Optimization

---------------------------



The solution has two configurations for PGO. The PGInstrument

configuration must be built first. The PGInstrument binaries are linked

against a profiling library and contain extra debug information. The

PGUpdate configuration takes the profiling data and generates optimized

binaries.



The build_pgo.bat script automates the creation of optimized binaries.

It creates the PGI files, runs the unit test suite or PyBench with the

PGI python, and finally creates the optimized files.



See

    http://msdn.microsoft.com/en-us/library/e7k32f4k(VS.100).aspx

for more on this topic.





Static library

--------------



The solution has no configuration for static libraries. However it is

easy to build a static library instead of a DLL. You simply have to set

the "Configuration Type" to "Static Library (.lib)" and alter the

preprocessor macro "Py_ENABLE_SHARED" to "Py_NO_ENABLE_SHARED". You may

also have to change the "Runtime Library" from "Multi-threaded DLL

(/MD)" to "Multi-threaded (/MT)".





Visual Studio properties

------------------------



The PCbuild solution makes heavy use of Visual Studio property files

(*.props). The properties can be viewed and altered in the Property

Manager (View -> Other Windows -> Property Manager).



The property files used are (+-- = "also imports"):

 * debug (debug macro: _DEBUG)

 * pginstrument (PGO)

 * pgupdate (PGO)

    +-- pginstrument

 * pyd (python extension, release build)

    +-- release

    +-- pyproject

 * pyd_d (python extension, debug build)

    +-- debug

    +-- pyproject

 * pyproject (base settings for all projects, user macros like PyDllName)

 * release (release macro: NDEBUG)

 * sqlite3 (used only by sqlite3.vcxproj)

 * x64 (AMD64 / x64 platform specific settings)



The pyproject property file defines _WIN32 and x64 defines _WIN64 and

_M_X64 although the macros are set by the compiler, too. The GUI doesn't

always know about the macros and confuse the user with false

information.





Your Own Extension DLLs

-----------------------



If you want to create your own extension module DLL (.pyd), there's an

example with easy-to-follow instructions in ..\PC\example\; read the

file readme.txt there first.