readme.txt
1 Quick Start Guide 2 ----------------- 3 4 1. Install Microsoft Visual Studio 2017 with Python workload and 5 Python native development component. 6 1a. Optionally install Python 3.6 or later. If not installed, 7 get_externals.bat (via build.bat) will download and use Python via 8 NuGet. 9 2. Run "build.bat" to build Python in 32-bit Release configuration. 10 3. (Optional, but recommended) Run the test suite with "rt.bat -q". 11 12 13 Building Python using Microsoft Visual C++ 14 ------------------------------------------ 15 16 This directory is used to build CPython for Microsoft Windows NT version 17 6.0 or higher (Windows Vista, Windows Server 2008, or later) on 32 and 64 18 bit platforms. Using this directory requires an installation of 19 Microsoft Visual Studio 2017 (MSVC 14.1) with the *Python workload* and 20 its optional *Python native development* component selected. (For 21 command-line builds, Visual Studio 2015 may also be used.) 22 23 Building from the command line is recommended in order to obtain any 24 external dependencies. To build, simply run the "build.bat" script without 25 any arguments. After this succeeds, you can open the "pcbuild.sln" 26 solution in Visual Studio to continue development. 27 28 To build an installer package, refer to the README in the Tools/msi folder. 29 30 The solution currently supports two platforms. The Win32 platform is 31 used to build standard x86-compatible 32-bit binaries, output into the 32 win32 sub-directory. The x64 platform is used for building 64-bit AMD64 33 (aka x86_64 or EM64T) binaries, output into the amd64 sub-directory. 34 The Itanium (IA-64) platform is no longer supported. 35 36 Four configuration options are supported by the solution: 37 Debug 38 Used to build Python with extra debugging capabilities, equivalent 39 to using ./configure --with-pydebug on UNIX. All binaries built 40 using this configuration have "_d" added to their name: 41 python37_d.dll, python_d.exe, parser_d.pyd, and so on. Both the 42 build and rt (run test) batch files in this directory accept a -d 43 option for debug builds. If you are building Python to help with 44 development of CPython, you will most likely use this configuration. 45 PGInstrument, PGUpdate 46 Used to build Python in Release configuration using PGO, which 47 requires Premium Edition of Visual Studio. See the "Profile 48 Guided Optimization" section below for more information. Build 49 output from each of these configurations lands in its own 50 sub-directory of this directory. The official Python releases may 51 be built using these configurations. 52 Release 53 Used to build Python as it is meant to be used in production 54 settings, though without PGO. 55 56 57 Building Python using the build.bat script 58 ---------------------------------------------- 59 60 In this directory you can find build.bat, a script designed to make 61 building Python on Windows simpler. This script will use the env.bat 62 script to detect either Visual Studio 2017 or 2015, either of 63 which may be used to build Python. Currently Visual Studio 2017 is 64 officially supported. 65 66 By default, build.bat will build Python in Release configuration for 67 the 32-bit Win32 platform. It accepts several arguments to change 68 this behavior, try `build.bat -h` to learn more. 69 70 71 C Runtime 72 --------- 73 74 Visual Studio 2017 uses version 14.0 of the C runtime (vcruntime140). 75 The executables no longer use the "Side by Side" assemblies used in 76 previous versions of the compiler. This simplifies distribution of 77 applications. 78 79 The run time libraries are available under the redist folder of your 80 Visual Studio distribution. For more info, see the Readme in the 81 redist folder. 82 83 84 Sub-Projects 85 ------------ 86 87 The CPython project is split up into several smaller sub-projects which 88 are managed by the pcbuild.sln solution file. Each sub-project is 89 represented by a .vcxproj and a .vcxproj.filters file starting with the 90 name of the sub-project. These sub-projects fall into a few general 91 categories: 92 93 The following sub-projects represent the bare minimum required to build 94 a functioning CPython interpreter. If nothing else builds but these, 95 you'll have a very limited but usable python.exe: 96 pythoncore 97 .dll and .lib 98 python 99 .exe 100 101 These sub-projects provide extra executables that are useful for running 102 CPython in different ways: 103 pythonw 104 pythonw.exe, a variant of python.exe that doesn't open a Command 105 Prompt window 106 pylauncher 107 py.exe, the Python Launcher for Windows, see 108 http://docs.python.org/3/using/windows.html#launcher 109 pywlauncher 110 pyw.exe, a variant of py.exe that doesn't open a Command Prompt 111 window 112 _testembed 113 _testembed.exe, a small program that embeds Python for testing 114 purposes, used by test_capi.py 115 116 These are miscellaneous sub-projects that don't really fit the other 117 categories: 118 _freeze_importlib 119 _freeze_importlib.exe, used to regenerate Python\importlib.h after 120 changes have been made to Lib\importlib\_bootstrap.py 121 pyshellext 122 pyshellext.dll, the shell extension deployed with the launcher 123 python3dll 124 python3.dll, the PEP 384 Stable ABI dll 125 xxlimited 126 builds an example module that makes use of the PEP 384 Stable ABI, 127 see Modules\xxlimited.c 128 129 The following sub-projects are for individual modules of the standard 130 library which are implemented in C; each one builds a DLL (renamed to 131 .pyd) of the same name as the project: 132 _asyncio 133 _ctypes 134 _ctypes_test 135 _decimal 136 _elementtree 137 _hashlib 138 _msi 139 _multiprocessing 140 _overlapped 141 _socket 142 _testbuffer 143 _testcapi 144 _testconsole 145 _testimportmultiple 146 _testmultiphase 147 _tkinter 148 pyexpat 149 select 150 unicodedata 151 winsound 152 153 The following Python-controlled sub-projects wrap external projects. 154 Note that these external libraries are not necessary for a working 155 interpreter, but they do implement several major features. See the 156 "Getting External Sources" section below for additional information 157 about getting the source for building these libraries. The sub-projects 158 are: 159 _bz2 160 Python wrapper for version 1.0.6 of the libbzip2 compression library 161 Homepage: 162 http://www.bzip.org/ 163 _lzma 164 Python wrapper for version 5.2.2 of the liblzma compression library 165 Homepage: 166 http://tukaani.org/xz/ 167 _ssl 168 Python wrapper for version 1.1.0h of the OpenSSL secure sockets 169 library, which is downloaded from our binaries repository at 170 https://github.com/python/cpython-bin-deps. 171 172 Homepage: 173 http://www.openssl.org/ 174 175 Building OpenSSL requires Perl on your path, and can be performed by 176 running PCbuild\prepare_ssl.bat. This will retrieve the version of 177 the sources matched to the current commit from the OpenSSL branch 178 in our source repository at 179 https://github.com/python/cpython-source-deps. 180 181 To use an alternative build of OpenSSL completely, you should replace 182 the files in the externals/openssl-bin-<version> folder with your own. 183 As long as this folder exists, its contents will not be downloaded 184 again when building. 185 186 _sqlite3 187 Wraps SQLite 3.21.0.0, which is itself built by sqlite3.vcxproj 188 Homepage: 189 http://www.sqlite.org/ 190 _tkinter 191 Wraps version 8.6.6 of the Tk windowing system, which is downloaded 192 from our binaries repository at 193 https://github.com/python/cpython-bin-deps. 194 195 Homepage: 196 http://www.tcl.tk/ 197 198 Building Tcl and Tk can be performed by running 199 PCbuild\prepare_tcltk.bat. This will retrieve the version of the 200 sources matched to the current commit from the Tcl and Tk branches 201 in our source repository at 202 https://github.com/python/cpython-source-deps. 203 204 The two projects install their respective components in a 205 directory alongside the source directories called "tcltk" on 206 Win32 and "tcltk64" on x64. They also copy the Tcl and Tk DLLs 207 into the current output directory, which should ensure that Tkinter 208 is able to load Tcl/Tk without having to change your PATH. 209 210 211 Getting External Sources 212 ------------------------ 213 214 The last category of sub-projects listed above wrap external projects 215 Python doesn't control, and as such a little more work is required in 216 order to download the relevant source files for each project before they 217 can be built. However, a simple script is provided to make this as 218 painless as possible, called "get_externals.bat" and located in this 219 directory. This script extracts all the external sub-projects from 220 https://github.com/python/cpython-source-deps 221 and 222 https://github.com/python/cpython-bin-deps 223 via a Python script called "get_external.py", located in this directory. 224 If Python 3.6 or later is not available via the "py.exe" launcher, the 225 path or command to use for Python can be provided in the PYTHON_FOR_BUILD 226 environment variable, or get_externals.bat will download the latest 227 version of NuGet and use it to download the latest "pythonx86" package 228 for use with get_external.py. Everything downloaded by these scripts is 229 stored in ..\externals (relative to this directory). 230 231 It is also possible to download sources from each project's homepage, 232 though you may have to change folder names or pass the names to MSBuild 233 as the values of certain properties in order for the build solution to 234 find them. This is an advanced topic and not necessarily fully 235 supported. 236 237 The get_externals.bat script is called automatically by build.bat 238 unless you pass the '-E' option. 239 240 241 Profile Guided Optimization 242 --------------------------- 243 244 The solution has two configurations for PGO. The PGInstrument 245 configuration must be built first. The PGInstrument binaries are linked 246 against a profiling library and contain extra debug information. The 247 PGUpdate configuration takes the profiling data and generates optimized 248 binaries. 249 250 The build_pgo.bat script automates the creation of optimized binaries. 251 It creates the PGI files, runs the unit test suite or PyBench with the 252 PGI python, and finally creates the optimized files. 253 254 See 255 http://msdn.microsoft.com/en-us/library/e7k32f4k(VS.140).aspx 256 for more on this topic. 257 258 259 Static library 260 -------------- 261 262 The solution has no configuration for static libraries. However it is 263 easy to build a static library instead of a DLL. You simply have to set 264 the "Configuration Type" to "Static Library (.lib)" and alter the 265 preprocessor macro "Py_ENABLE_SHARED" to "Py_NO_ENABLE_SHARED". You may 266 also have to change the "Runtime Library" from "Multi-threaded DLL 267 (/MD)" to "Multi-threaded (/MT)". 268 269 270 Visual Studio properties 271 ------------------------ 272 273 The PCbuild solution makes use of Visual Studio property files (*.props) 274 to simplify each project. The properties can be viewed in the Property 275 Manager (View -> Other Windows -> Property Manager) but should be 276 carefully modified by hand. 277 278 The property files used are: 279 * python (versions, directories and build names) 280 * pyproject (base settings for all projects) 281 * openssl (used by projects dependent upon OpenSSL) 282 * tcltk (used by _tkinter, tcl, tk and tix projects) 283 284 The pyproject property file defines all of the build settings for each 285 project, with some projects overriding certain specific values. The GUI 286 doesn't always reflect the correct settings and may confuse the user 287 with false information, especially for settings that automatically adapt 288 for diffirent configurations. 289
