3 --------------------------
4 Frequently Asked Questions
5 --------------------------
7 Is Pigweed a framework?
8 -----------------------
9 There are three core components of Pigweed's offering:
11 1. The environment setup system (bootstrap and activate)
12 2. The GN-based build and test system
13 3. The individual modules (mostly C++ code)
15 We consider #1 and #2 combined as the "Pigweed Monolith" - since it has an
16 integrated environment setup and build system. However, this part of the system
17 is entirely optional; it is not only possible, but encouraged to take
18 individual modules (like for example ``pw_tokenizer`` or ``pw_ring_buffer``)
19 and integrate them into your existing environment setup approach and build
22 So, to answer the question:
24 1. **Is Pigweed's environment setup system a framework?** No. This component
25 solves (a) downloading compilers and (b) setting up a Python virtual
26 environment; what you do with the environment is up to you.
27 2. **Is Pigweed's GN-based build & test setup system a framework?** In short,
28 yes. This is the most framework-like part of Pigweed, since you build your
29 code using Pigweed's GN-based primitives. However, it is optional.
30 3. **Are Pigweed's C++ modules a framework?** No. They are libraries you can
31 independently take into your project and use like any other C++ library.
33 Isn't C++ bloated and slow?
34 ---------------------------
35 In general, no, but it is important to follow some guidelines as discussed in
36 the :ref:`Embedded C++ Guide <docs-embedded-cpp>`.
38 At Google, we have made some quantitative analysis of various common embedded
39 patterns in C++ to evaluate the cost of various constructs. We will open source
40 this work at some point.
42 How do I setup Pigweed for my project?
43 --------------------------------------
47 This FAQ entry should be an entire article, but isn't one yet; sorry!
49 To use Pigweed, you must decide the answer to one question: Do you wish to use
50 the Pigweed integrated environment and build, or just use individual modules?
52 A la carte: Individual modules only
53 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
54 This is best option if you have an existing project, with pre-existing build in
57 To use the libraries, submodule or copy the relevant Pigweed modules into your
58 project, and use them like any other C++ library. You can reference the
59 existing GN files or CMake files when doing this. In the case of CMake, you can
60 directly import Pigweed's build from your project with CMake's external project
61 system, or just use a CMake include statement.
63 Monolith: Using the integrated system
64 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
65 This may be a good option if you are starting a new project. However,
66 there is a gap in our documentation and examples at the moment; sorry about
67 that! You may need to ask us for help; try the mailing list or chat room.
69 Note: Pigweed isn't quite ready for masses of projects to use the whole system
70 just yet. We will be offering examples and material for this eventually.
74 - Create a new repository
75 - Add Pigweed as a submodule; we suggest under ``third_party/pigweed`` or
76 ``vendor/pigweed``. It is also possible to use Android's repo tool, but we
78 - Create your own ``BUILD.gn`` and ``BUILDCONFIG.gn``; we suggest starting by
79 copying the ones from Pigweed. You'll need to create your own toplevel
80 targets like those in Pigweed's root ``BUILD.gn``.
81 - Create a bootstrap script in your project root that optionally does some
82 project specific setup, then invokes the Pigweed upstream bootstrap (or in
84 - If you have custom hardware, you will want to create a *target*. See the
85 `targets/` directory for examples like the STM32F429i-Discovery.
89 This section is incomplete; if you need help please reach out in chat or on
90 the mailing list. We know this part of Pigweed is incomplete and will help
91 those who are interested in giving Pigweed a try.
93 What development hosts are supported?
94 -------------------------------------
95 We support the following platforms:
97 +-------------------------------+---------------------------------------+
98 | **Development host** | **Comments** |
99 +-------------------------------+---------------------------------------+
100 | Linux on x86-64 | Most recent Linux distributions |
102 +-------------------------------+---------------------------------------+
103 | macOS on x86-64 | Mojave or newer should work. |
104 +-------------------------------+---------------------------------------+
105 | Windows 10 on x86-64 | Native Windows only; WSL1 or 2 not |
107 +-------------------------------+---------------------------------------+
108 | Docker on x86-64 | Containers based on Ubuntu 18.04 |
110 +-------------------------------+---------------------------------------+
114 In all of the above supported platforms, the support is contingent on using
115 Pigweed's bootstrap (env setup) system. While it is possible to use Pigweed
116 without bootstrap, it is unsupported and undocumented at this time.
118 Partially supported host platform: Chrome OS
119 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
120 Chromebooks are able to run some of the Pigweed components; notably all the
121 "host" target builds and runs. However, due to USB access issues, it is not
122 possible to flash and run on real hardware (like for example the STM32F429i
127 1. `Enable the Linux shell <https://support.google.com/chromebook/answer/9145439>`_
128 2. ``sudo apt-install build-essential``
129 3. Go through Pigweed setup.
131 What about other host platforms?
132 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
133 There are two key issues that make running the host tooling on other platforms
136 1. Availability of up-to-date compilers
137 2. Availability of up-to-date Python
139 For both of these, Pigweed relies on Google-maintained binaries packaged in
140 CIPD, which includes daily builds of LLVM, and recent versions of the ARM GCC
141 toolchains. Platforms other than Mac/Windows/Linux running on x86-64 will need
142 to provide equivalent binaries, which is some effort.
144 Host platforms that we are likely to support in the future
145 ..........................................................
147 - **Linux on ARM** - At time of writing (mid 2020), we do not support ARM-based
148 host platforms. However, we would like to support this eventually.
149 - **Windows on WSL2 x86-64** - There are some minor issues preventing WSL2 on
150 Windows from being a smooth experience, but we are working on them.
152 Platforms that we are unlikely to support
153 .........................................
155 - **Anything on x86-32** - While it's possible 32-bit x86 could be made to
156 work, we don't have enough users to make this worthwhile. If this is
157 something you are interested in and would be willing to support, let us know.
159 Why name the project Pigweed?
160 -----------------------------
161 Pigweed, also known as amaranth, is a nutritious grain and leafy salad green
162 that is also a rapidly growing weed. When developing the project that
163 eventually became Pigweed, we wanted to find a name that was fun, playful, and
164 reflective of how we saw Pigweed growing. Teams would start out using one
165 module that catches their eye, and after that goes well, they’d quickly start