zig/README.md

Zig is an open-source programming language designed for robustness, optimality, and maintainability.

Download & Documentation

Feature Highlights

• Small, simple language. Focus on debugging your application rather than debugging knowledge of your programming language.
• Ships with a build system that obviates the need for a configure script or a makefile. In fact, existing C and C++ projects may choose to depend on Zig instead of e.g. cmake.
• A fresh take on error handling which makes writing correct code easier than writing buggy code.
• Debug mode optimizes for fast compilation time and crashing with a stack trace when undefined behavior would happen.
• ReleaseFast mode produces heavily optimized code. What other projects call "Link Time Optimization" Zig does automatically.
• Compatible with C libraries with no wrapper necessary. Directly include C .h files and get access to the functions and symbols therein.
• Provides standard library which competes with the C standard library and is always compiled against statically in source form. Zig binaries do not depend on libc unless explicitly linked.
• Optional type instead of null pointers.
• Safe unions, tagged unions, and C ABI compatible unions.
• Generics so that one can write efficient data structures that work for any data type.
• No header files required. Top level declarations are entirely order-independent.
• Compile-time code execution. Compile-time reflection.
• Partial compile-time function evaluation which eliminates the need for a preprocessor or macros.
• The binaries produced by Zig have complete debugging information so you can, for example, use GDB, MSVC, or LLDB to debug your software.
• Built-in unit tests with zig test.
• Friendly toward package maintainers. Reproducible build, bootstrapping process carefully documented. Issues filed by package maintainers are considered especially important.
• Cross-compiling is a primary use case.
• In addition to creating executables, creating a C library is a primary use case. You can export an auto-generated .h file.

Supported Targets

Tier 1 Support

• Not only can Zig generate machine code for these targets, but the standard library cross-platform abstractions have implementations for these targets. Thus it is practical to write a pure Zig application with no dependency on libc.
• The CI server automatically tests these targets on every commit to master branch, and updates ziglang.org/download with links to pre-built binaries.
• These targets have debug info capabilities and therefore produce stack traces on failed assertions.
• (coming soon) libc is available for this target even when cross compiling.

Tier 2 Support

• There may be some standard library implementations, but many abstractions will give an "Unsupported OS" compile error. One can link with libc or other libraries to fill in the gaps in the standard library.
• These targets are known to work, but are not automatically tested, so there are occasional regressions.
• Some tests may be disabled for these targets as we work toward Tier 1 support.

Tier 3 Support

• The standard library has little to no knowledge of the existence of this target.
• Because Zig is based on LLVM, it has the capability to build for these targets, and LLVM has the target enabled by default.
• These targets are not frequently tested; one will likely need to contribute to Zig in order to build for these targets.
• The Zig compiler might need to be updated with a few things such as
  • what sizes are the C integer types
  • C ABI calling convention for this target
  • bootstrap code and default panic handler
• zig targets is guaranteed to include this target.

Tier 4 Support

• Support for these targets is entirely experimental.
• LLVM may have the target as an experimental target, which means that you need to use Zig-provided binaries for the target to be available, or build LLVM from source with special configure flags. zig targets will display the target if it is available.
• This target may be considered deprecated by an official party, such as macosx/i386 in which case this target will remain forever stuck in Tier 4.
• This target may only support --emit asm and cannot emit object files.

Support Table

	freestanding	linux	macosx	windows	freebsd	netbsd	UEFI	other
x86_64	Tier 2	Tier 1	Tier 1	Tier 1	Tier 2	Tier 2	Tier 2	Tier 3
i386	Tier 2	Tier 2	Tier 4	Tier 2	Tier 3	Tier 3	Tier 3	Tier 3
arm	Tier 2	Tier 3	Tier 3	Tier 3	Tier 3	Tier 3	Tier 3	Tier 3
arm64	Tier 2	Tier 2	Tier 3	Tier 3	Tier 3	Tier 3	Tier 3	Tier 3
wasm32	Tier 2	N/A	N/A	N/A	N/A	N/A	N/A	Tier 2
bpf	Tier 3	Tier 3	N/A	N/A	Tier 3	Tier 3	N/A	Tier 3
hexagon	Tier 3	Tier 3	N/A	N/A	Tier 3	Tier 3	N/A	Tier 3
mips	Tier 3	Tier 3	N/A	N/A	Tier 3	Tier 3	N/A	Tier 3
powerpc32	Tier 3	Tier 3	Tier 4	N/A	Tier 3	Tier 3	N/A	Tier 3
powerpc64	Tier 3	Tier 3	Tier 4	N/A	Tier 3	Tier 3	N/A	Tier 3
amdgcn	Tier 3	Tier 3	N/A	N/A	Tier 3	Tier 3	N/A	Tier 3
sparc	Tier 3	Tier 3	N/A	N/A	Tier 3	Tier 3	N/A	Tier 3
s390x	Tier 3	Tier 3	N/A	N/A	Tier 3	Tier 3	N/A	Tier 3
lanai	Tier 3	Tier 3	N/A	N/A	Tier 3	Tier 3	N/A	Tier 3
wasm64	Tier 4	N/A	N/A	N/A	N/A	N/A	N/A	N/A
avr	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
riscv32	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	Tier 4	Tier 4
riscv64	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	Tier 4	Tier 4
xcore	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
nvptx	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
msp430	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
r600	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
arc	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
tce	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
le	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
amdil	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
hsail	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
spir	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
kalimba	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
shave	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4
renderscript	Tier 4	Tier 4	N/A	N/A	Tier 4	Tier 4	N/A	Tier 4

Community

• IRC: #zig on Freenode (Channel Logs).
• Reddit: /r/zig
• Email list: ~andrewrk/ziglang@lists.sr.ht

Building from Source

Note that you can download a binary of master branch.

Stage 1: Build Zig from C++ Source Code

Dependencies

POSIX

• cmake >= 2.8.5
• gcc >= 5.0.0 or clang >= 3.6.0
• LLVM, Clang, LLD development libraries == 8.x, compiled with the same gcc or clang version above
  • Use the system package manager, or build from source.

Windows

• cmake >= 2.8.5
• Microsoft Visual Studio 2017 (version 15.8)
• LLVM, Clang, LLD development libraries == 8.x, compiled with the same MSVC version above
  • Use the pre-built binaries or build from source.

Instructions

POSIX

mkdir build
cd build
cmake ..
make install

MacOS

brew install cmake llvm@8
brew outdated llvm@8 || brew upgrade llvm@8
mkdir build
cd build
cmake .. -DCMAKE_PREFIX_PATH=/usr/local/Cellar/llvm/8.0.0
make install

Windows

See https://github.com/ziglang/zig/wiki/Building-Zig-on-Windows

Stage 2: Build Self-Hosted Zig from Zig Source Code

Note: Stage 2 compiler is not complete. Beta users of Zig should use the Stage 1 compiler for now.

Dependencies are the same as Stage 1, except now you can use stage 1 to compile Zig code.

bin/zig build --build-file ../build.zig --prefix $(pwd)/stage2 install

This produces ./stage2/bin/zig which can be used for testing and development. Once it is feature complete, it will be used to build stage 3 - the final compiler binary.

Stage 3: Rebuild Self-Hosted Zig Using the Self-Hosted Compiler

Note: Stage 2 compiler is not yet able to build Stage 3. Building Stage 3 is not yet supported.

Once the self-hosted compiler can build itself, this will be the actual compiler binary that we will install to the system. Until then, users should use stage 1.

Debug / Development Build

./stage2/bin/zig build --build-file ../build.zig --prefix $(pwd)/stage3 install

Release / Install Build

./stage2/bin/zig build --build-file ../build.zig install -Drelease-fast

Contributing

Start a Project Using Zig

One of the best ways you can contribute to Zig is to start using it for a personal project. Here are some great examples:

• Oxid - arcade style game
• TM35-Metronome - tools for modifying and randomizing Pokémon games
• trOS - tiny aarch64 baremetal OS thingy

Without fail, these projects lead to discovering bugs and helping flesh out use cases, which lead to further design iterations of Zig. Importantly, each issue found this way comes with a real world motivations, so it is easy to explain your reasoning behind proposals and feature requests.

Ideally, such a project will help you to learn new skills and add something to your personal portfolio at the same time.

Spread the Word

Another way to contribute is to write about Zig, or speak about Zig at a conference, or do either of those things for your project which uses Zig. Here are some examples:

• Iterative Replacement of C with Zig
• The Right Tool for the Right Job: Redis Modules & Zig

Zig is a brand new language, with no advertising budget. Word of mouth is the only way people find out about the project, and the more people hear about it, the more people will use it, and the better chance we have to take over the world.

Finding Contributor Friendly Issues

Please note that issues labeled Proposal but do not also have the Accepted label are still under consideration, and efforts to implement such a proposal have a high risk of being wasted. If you are interested in a proposal which is still under consideration, please express your interest in the issue tracker, providing extra insights and considerations that others have not yet expressed. The most highly regarded argument in such a discussion is a real world use case.

The issue label Contributor Friendly exists to help contributors find issues that are "limited in scope and/or knowledge of Zig internals."

Editing Source Code

First, build the Stage 1 compiler as described in the Building section.

When making changes to the standard library, be sure to edit the files in the std directory and not the installed copy in the build directory. If you add a new file to the standard library, you must also add the file path in CMakeLists.txt.

To test changes, do the following from the build directory:

1. Run make install (on POSIX) or msbuild -p:Configuration=Release INSTALL.vcxproj (on Windows).
2. bin/zig build --build-file ../build.zig test (on POSIX) or bin\zig.exe build --build-file ..\build.zig test (on Windows).

That runs the whole test suite, which does a lot of extra testing that you likely won't always need, and can take upwards of 2 hours. This is what the CI server runs when you make a pull request.

To save time, you can add the --help option to the zig build command and see what options are available. One of the most helpful ones is -Dskip-release. Adding this option to the command in step 2 above will take the time down from around 2 hours to about 6 minutes, and this is a good enough amount of testing before making a pull request.

Another example is choosing a different set of things to test. For example, test-std instead of test will only run the standard library tests, and not the other ones. Combining this suggestion with the previous one, you could do this:

bin/zig build --build-file ../build.zig test-std -Dskip-release (on POSIX) or bin\zig.exe build --build-file ..\build.zig test-std -Dskip-release (on Windows).

This will run only the standard library tests, in debug mode only, for all targets (it will cross-compile the tests for non-native targets but not run them).

When making changes to the compiler source code, the most helpful test step to run is test-behavior. When editing documentation it is docs. You can find this information and more in the --help menu.