# Portable C and C++ Development Kit for x64 Windows
[w64devkit][] is a Dockerfile that builds from source a small, portable
development suite for creating C and C++ applications on and for x64
Windows. See "Releases" for pre-built, ready-to-use kits.
Included tools:
* [Mingw-w64 GCC][w64] : compilers, linker, assembler
* [GDB][gdb] : debugger
* [GNU Make][make] : standard build tool
* [busybox-w32][bb] : standard unix utilities, including sh
* [Vim][vim] : powerful text editor
* [Universal Ctags][ctags] : source navigation
* [NASM][nasm] : x86 assembler
* [Cppcheck][cppcheck] : static code analysis
The toolchain includes pthreads, C++11 threads, and OpenMP. All included
runtime components are static. **Docker/Podman is not required to use the
development kit**. It's merely a reliable, clean environment for building
the kit itself.
## Build
First build the image, then run it to produce a distribution .zip file:
docker build -t w64devkit .
docker run --rm w64devkit >w64devkit.zip
This takes about half an hour on modern systems. You will need an internet
connection during the first few minutes of the build. **Note:** Do not use
PowerShell because it lacks file redirection.
## Usage
The final .zip file contains tools in a typical unix-like configuration.
Unzip the contents anywhere. Inside is `w64devkit.exe`, which launches a
console window with the environment configured and ready to go. It is the
easiest way to enter the development environment, and requires no system
changes. It also sets two extra environment variables: `W64DEVKIT_HOME` to
the installation root and `W64DEVKIT` to the version.
Alternatively, add the `bin/` directory to your path. For example, inside
a `cmd.exe` console or batch script:
set PATH=c:\path\to\w64devkit\bin;%PATH%
Then to start an interactive unix shell:
sh -l
## Main features
* No installation required. Run it anywhere as any user. Simply delete
when no longer needed.
* Fully offline. No internet access is ever required or attempted.
* A focus on static linking all runtime components. The runtime is
optimized for size.
* Trivial to build from source, meaning it's easy to tweak and adjust any
part of the kit for your own requirements.
* [Complements Go](https://nullprogram.com/blog/2021/06/29/) for cgo and
bootstrapping.
## Optimized for size
The language runtimes in w64devkit are optimized for size, so it produces
particularly small binaries when programs are also optimized for size
(`-Os`) during compilation. If your program only uses the `printf` family
of functions with MSVC-compatible directives (i.e. limited to C89), and
you want even smaller binaries, you can avoid embedding the Mingw-w64's
improved implementation by setting `__USE_MINGW_ANSI_STDIO` to 0 before
including any headers.
$ cc -Os -D__USE_MINGW_ANSI_STDIO=0 ...
## Fortran support
Only C and C++ are included by default, but w64devkit also has full
support for Fortran. To build a Fortran compiler, add `fortran` to the
`--enable-languages` lines in the Dockerfile.
## Recommended downloadable, offline documentation
With a few exceptions, such as Vim's built-in documentation (`:help`),
w64devkit does not include documentation. However, you need not forgo
offline documentation alongside your offline development tools. This is a
list of recommended, no-cost, downloadable documentation complementing
w64devkit's capabilities. In rough order of importance:
* [cppreference][doc-cpp] (HTML), friendly documentation for the C and C++
standard libraries.
* [GCC manuals][doc-gcc] (PDF, HTML), to reference GCC features,
especially built-ins, intrinsics, and command line switches.
* [Win32 Help File][doc-win32] (CHM) is old, but official, Windows API
documentation. Unfortunately much is missing, such as Winsock. (Offline
Windows documentation has always been very hard to come by.)
* [C and C++ Standards (drafts)][doc-std] (PDF), for figuring out how
corner cases are intended to work.
* [Intel Intrinsics Guide][doc-intr] (interactive HTML), a great resource
when working with SIMD intrinsics. (Search for "Download" on the left.)
* [GNU Make manual][doc-make] (PDF, HTML)
* [GNU Binutils manuals][doc-ld] (PDF, HTML), particularly `ld` and `as`.
* [GDB manual][doc-gdb] (PDF)
* [BusyBox man pages][doc-bb] (TXT), though everything here is also
available via `-h` option inside w64devkit.
* [NASM manual][doc-nasm] (PDF)
* [Intel Software Developer Manuals][doc-intel] (PDF), for referencing x86
instructions, when either studying compiler output with `objdump`, or
writing assembly with `nasm` or `as`.
## Library installation
Except for the standard libraries and Win32 import libraries, w64devkit
does not include libraries, but you can install additional libraries such
that the toolchain can find them naturally. There are three options:
1. Install it under the sysroot at `w64devkit/$ARCH/`. The easiest option,
but will require re-installation after upgrading w64devkit. If it
defines `.pc` files, the `pkg-config` command will automatically find
and use them.
2. Append its installation directory to your `CPATH` and `LIBRARY_PATH`
environment variables. Use `;` to delimit directories. You would likely
do this in your `.profile`.
3. If it exists, append its `pkgconfig` directory to the `PKG_CONFIG_PATH`
environment variable, then use the `pkg-config` command as usual. Use
`;` to delimit directories
Both (1) and (3) are designed to work correctly even if w64devkit or the
libraries have paths containing spaces.
## Cppcheck tips
Use `--library=windows` for programs calling the Win32 API directly, which
adds additional checks. In general, the following configuration is a good
default for programs developed using w64devkit:
$ cppcheck --quiet -j$(nproc) --library=windows \
--suppress=uninitvar --enable=portability,performance .
A "strict" check that is more thorough, but more false positives:
$ cppcheck --quiet -j$(nproc) --library=windows \
--enable=portability,performance,style \
--suppress=uninitvar --suppress=unusedStructMember \
--suppress=constVariable --suppress=shadowVariable \
--suppress=variableScope --suppress=constParameter \
--suppress=shadowArgument --suppress=knownConditionTrueFalse .
## Notes
`$HOME` can be set through the adjacent `w64devkit.ini` configuration, and
may even be relative to the `w64devkit/` directory. This is useful for
encapsulating the entire development environment, with home directory, on
removable, even read-only, media. Use a `.profile` in the home directory
to configure the environment further.
I'd love to include Git, but unfortunately Git's build system doesn't
quite support cross-compilation. A decent alternative would be
[Quilt][quilt], but it's written in Bash and Perl.
Neither Address Sanitizer (ASan) nor Thread Sanitizer (TSan) [has been
ported to Mingw-w64][san] ([also][san2]), but Undefined Behavior Sanitizer
(UBSan) works perfectly under GDB. With both `-fsanitize=undefined` and
`-fsanitize-trap`, GDB will [break precisely][break] on undefined
behavior, and it does not require linking with libsanitizer.
The kit includes a unique [`debugbreak` command][debugbreak]. It causes
all debugee processes to break in the debugger, like using Windows' F12
debugger hotkey. This is especially useful for console subsystem programs.
Since the build environment is so stable and predicable, it would be
great for the .zip to be reproducible, i.e. builds by different people
are bit-for-bit identical. There are multiple reasons why this is not
currently the case, the least of which are [timestamps in the .zip
file][zip].
## Licenses
When distributing binaries built using w64devkit, your .exe will include
parts of this distribution. For the GCC runtime, including OpenMP, you're
covered by the [GCC Runtime Library Exception][gpl] so you do not need to
do anything. Howeve