1![libuv][libuv_banner]
2
3## Overview
4
5libuv is a multi-platform support library with a focus on asynchronous I/O. It
6was primarily developed for use by [Node.js][], but it's also
7used by [Luvit](http://luvit.io/), [Julia](http://julialang.org/),
8[pyuv](https://github.com/saghul/pyuv), and [others](https://github.com/libuv/libuv/wiki/Projects-that-use-libuv).
9
10## Feature highlights
11
12 * Full-featured event loop backed by epoll, kqueue, IOCP, event ports.
13
14 * Asynchronous TCP and UDP sockets
15
16 * Asynchronous DNS resolution
17
18 * Asynchronous file and file system operations
19
20 * File system events
21
22 * ANSI escape code controlled TTY
23
24 * IPC with socket sharing, using Unix domain sockets or named pipes (Windows)
25
26 * Child processes
27
28 * Thread pool
29
30 * Signal handling
31
32 * High resolution clock
33
34 * Threading and synchronization primitives
35
36## Versioning
37
38Starting with version 1.0.0 libuv follows the [semantic versioning](http://semver.org/)
39scheme. The API change and backwards compatibility rules are those indicated by
40SemVer. libuv will keep a stable ABI across major releases.
41
42The ABI/API changes can be tracked [here](http://abi-laboratory.pro/tracker/timeline/libuv/).
43
44## Licensing
45
46libuv is licensed under the MIT license. Check the [LICENSE file](LICENSE).
47The documentation is licensed under the CC BY 4.0 license. Check the [LICENSE-docs file](LICENSE-docs).
48
49## Community
50
51 * [Support](https://github.com/libuv/help)
52 * [Mailing list](http://groups.google.com/group/libuv)
53 * [IRC chatroom (#libuv@irc.freenode.org)](http://webchat.freenode.net?channels=libuv&uio=d4)
54
55## Documentation
56
57### Official documentation
58
59Located in the docs/ subdirectory. It uses the [Sphinx](http://sphinx-doc.org/)
60framework, which makes it possible to build the documentation in multiple
61formats.
62
63Show different supported building options:
64
65```bash
66$ make help
67```
68
69Build documentation as HTML:
70
71```bash
72$ make html
73```
74
75Build documentation as HTML and live reload it when it changes (this requires
76sphinx-autobuild to be installed and is only supported on Unix):
77
78```bash
79$ make livehtml
80```
81
82Build documentation as man pages:
83
84```bash
85$ make man
86```
87
88Build documentation as ePub:
89
90```bash
91$ make epub
92```
93
94NOTE: Windows users need to use make.bat instead of plain 'make'.
95
96Documentation can be browsed online [here](http://docs.libuv.org).
97
98The [tests and benchmarks](https://github.com/libuv/libuv/tree/master/test)
99also serve as API specification and usage examples.
100
101### Other resources
102
103 * [LXJS 2012 talk](http://www.youtube.com/watch?v=nGn60vDSxQ4)
104   — High-level introductory talk about libuv.
105 * [libuv-dox](https://github.com/thlorenz/libuv-dox)
106   — Documenting types and methods of libuv, mostly by reading uv.h.
107 * [learnuv](https://github.com/thlorenz/learnuv)
108   — Learn uv for fun and profit, a self guided workshop to libuv.
109
110These resources are not handled by libuv maintainers and might be out of
111date. Please verify it before opening new issues.
112
113## Downloading
114
115libuv can be downloaded either from the
116[GitHub repository](https://github.com/libuv/libuv)
117or from the [downloads site](http://dist.libuv.org/dist/).
118
119Before verifying the git tags or signature files, importing the relevant keys
120is necessary. Key IDs are listed in the
121[MAINTAINERS](https://github.com/libuv/libuv/blob/master/MAINTAINERS.md)
122file, but are also available as git blob objects for easier use.
123
124Importing a key the usual way:
125
126```bash
127$ gpg --keyserver pool.sks-keyservers.net --recv-keys AE9BC059
128```
129
130Importing a key from a git blob object:
131
132```bash
133$ git show pubkey-saghul | gpg --import
134```
135
136### Verifying releases
137
138Git tags are signed with the developer's key, they can be verified as follows:
139
140```bash
141$ git verify-tag v1.6.1
142```
143
144Starting with libuv 1.7.0, the tarballs stored in the
145[downloads site](http://dist.libuv.org/dist/) are signed and an accompanying
146signature file sit alongside each. Once both the release tarball and the
147signature file are downloaded, the file can be verified as follows:
148
149```bash
150$ gpg --verify libuv-1.7.0.tar.gz.sign
151```
152
153## Build Instructions
154
155For GCC there are two build methods: via autotools or via [GYP][].
156GYP is a meta-build system which can generate MSVS, Makefile, and XCode
157backends. It is best used for integration into other projects.
158
159To build with autotools:
160
161```bash
162$ sh autogen.sh
163$ ./configure
164$ make
165$ make check
166$ make install
167```
168
169To build with [CMake](https://cmake.org/):
170
171```bash
172$ mkdir -p out/cmake ; cd out/cmake   # create build directory
173$ cmake ../.. -DBUILD_TESTING=ON      # generate project with test
174$ cmake --build .                     # build
175$ ctest -C Debug --output-on-failure  # run tests
176
177# Or manually run tests:
178$ ./out/cmake/uv_run_tests    # shared library build
179$ ./out/cmake/uv_run_tests_a  # static library build
180```
181
182To build with GYP, first run:
183
184```bash
185$ git clone https://chromium.googlesource.com/external/gyp build/gyp
186```
187
188### Windows
189
190Prerequisites:
191
192* [Python 2.6 or 2.7][] as it is required
193  by [GYP][].
194  If python is not in your path, set the environment variable `PYTHON` to its
195  location. For example: `set PYTHON=C:\Python27\python.exe`
196* One of:
197  * [Visual C++ Build Tools][]
198  * [Visual Studio 2015 Update 3][], all editions
199    including the Community edition (remember to select
200    "Common Tools for Visual C++ 2015" feature during installation).
201  * [Visual Studio 2017][], any edition (including the Build Tools SKU).
202    **Required Components:** "MSbuild", "VC++ 2017 v141 toolset" and one of the
203    Windows SDKs (10 or 8.1).
204* Basic Unix tools required for some tests,
205  [Git for Windows][] includes Git Bash
206  and tools which can be included in the global `PATH`.
207
208To build, launch a git shell (e.g. Cmd or PowerShell), run `vcbuild.bat`
209(to build with VS2017 you need to explicitly add a `vs2017` argument),
210which will checkout the GYP code into `build/gyp`, generate `uv.sln`
211as well as the necesery related project files, and start building.
212
213```console
214> vcbuild
215```
216
217Or:
218
219```console
220> vcbuild vs2017
221```
222
223To run the tests:
224
225```console
226> vcbuild test
227```
228
229To see all the options that could passed to `vcbuild`:
230
231```console
232> vcbuild help
233vcbuild.bat [debug/release] [test/bench] [clean] [noprojgen] [nobuild] [vs2017] [x86/x64] [static/shared]
234Examples:
235  vcbuild.bat              : builds debug build
236  vcbuild.bat test         : builds debug build and runs tests
237  vcbuild.bat release bench: builds release build and runs benchmarks
238```
239
240
241### Unix
242
243For Debug builds (recommended) run:
244
245```bash
246$ ./gyp_uv.py -f make
247$ make -C out
248```
249
250For Release builds run:
251
252```bash
253$ ./gyp_uv.py -f make
254$ BUILDTYPE=Release make -C out
255```
256
257Run `./gyp_uv.py -f make -Dtarget_arch=x32` to build [x32][] binaries.
258
259### OS X
260
261Run:
262
263```bash
264$ ./gyp_uv.py -f xcode
265$ xcodebuild -ARCHS="x86_64" -project out/uv.xcodeproj -configuration Release -alltargets
266```
267
268Using Homebrew:
269
270```bash
271$ brew install --HEAD libuv
272```
273
274Note to OS X users:
275
276Make sure that you specify the architecture you wish to build for in the
277"ARCHS" flag. You can specify more than one by delimiting with a space
278(e.g. "x86_64 i386").
279
280### Android
281
282Run:
283
284For arm
285
286```bash
287$ source ./android-configure-arm NDK_PATH gyp [API_LEVEL]
288$ make -C out
289```
290
291or for arm64
292
293```bash
294$ source ./android-configure-arm64 NDK_PATH gyp [API_LEVEL]
295$ make -C out
296```
297
298or for x86
299
300```bash
301$ source ./android-configure-x86 NDK_PATH gyp [API_LEVEL]
302$ make -C out
303```
304
305or for x86_64
306
307```bash
308$ source ./android-configure-x86_64 NDK_PATH gyp [API_LEVEL]
309$ make -C out
310```
311
312The default API level is 24, but a different one can be selected as follows:
313
314```bash
315$ source ./android-configure-arm ~/android-ndk-r15b gyp 21
316$ make -C out
317```
318
319Note for UNIX users: compile your project with `-D_LARGEFILE_SOURCE` and
320`-D_FILE_OFFSET_BITS=64`. GYP builds take care of that automatically.
321
322### Using Ninja
323
324To use ninja for build on ninja supported platforms, run:
325
326```bash
327$ ./gyp_uv.py -f ninja
328$ ninja -C out/Debug     #for debug build OR
329$ ninja -C out/Release
330```
331
332
333### Running tests
334
335#### Build
336
337Build (includes tests):
338
339```bash
340$ ./gyp_uv.py -f make
341$ make -C out
342```
343
344#### Run all tests
345
346```bash
347$ ./out/Debug/run-tests
348```
349
350#### Run one test
351
352The list of all tests is in `test/test-list.h`.
353
354This invocation will cause the `run-tests` driver to fork and execute `TEST_NAME` in a child process:
355
356```bash
357$ ./out/Debug/run-tests TEST_NAME
358```
359
360This invocation will cause the `run-tests` driver to execute the test within the `run-tests` process:
361
362```bash
363$ ./out/Debug/run-tests TEST_NAME TEST_NAME
364```
365
366#### Debugging tools
367
368When running the test from within the `run-tests` process (`run-tests TEST_NAME TEST_NAME`), tools like gdb and valgrind work normally.
369When running the test from a child of the `run-tests` process (`run-tests TEST_NAME`), use these tools in a fork-aware manner.
370
371##### Fork-aware gdb
372
373Use the [follow-fork-mode](https://sourceware.org/gdb/onlinedocs/gdb/Forks.html) setting:
374
375```
376$ gdb --args out/Debug/run-tests TEST_NAME
377
378(gdb) set follow-fork-mode child
379...
380```
381
382##### Fork-aware valgrind
383
384Use the `--trace-children=yes` parameter:
385
386```bash
387$ valgrind --trace-children=yes -v --tool=memcheck --leak-check=full --track-origins=yes --leak-resolution=high --show-reachable=yes --log-file=memcheck-%p.log out/Debug/run-tests TEST_NAME
388```
389
390### Running benchmarks
391
392See the section on running tests.
393The benchmark driver is `out/Debug/run-benchmarks` and the benchmarks are listed in `test/benchmark-list.h`.
394
395## Supported Platforms
396
397Check the [SUPPORTED_PLATFORMS file](SUPPORTED_PLATFORMS.md).
398
399### AIX Notes
400
401AIX compilation using IBM XL C/C++ requires version 12.1 or greater.
402
403AIX support for filesystem events requires the non-default IBM `bos.ahafs`
404package to be installed.  This package provides the AIX Event Infrastructure
405that is detected by `autoconf`.
406[IBM documentation](http://www.ibm.com/developerworks/aix/library/au-aix_event_infrastructure/)
407describes the package in more detail.
408
409AIX support for filesystem events is not compiled when building with `gyp`.
410
411### z/OS Notes
412
413z/OS creates System V semaphores and message queues. These persist on the system
414after the process terminates unless the event loop is closed.
415
416Use the `ipcrm` command to manually clear up System V resources.
417
418## Patches
419
420See the [guidelines for contributing][].
421
422[node.js]: http://nodejs.org/
423[GYP]: http://code.google.com/p/gyp/
424[guidelines for contributing]: https://github.com/libuv/libuv/blob/master/CONTRIBUTING.md
425[libuv_banner]: https://raw.githubusercontent.com/libuv/libuv/master/img/banner.png
426[x32]: https://en.wikipedia.org/wiki/X32_ABI
427[Python 2.6 or 2.7]: https://www.python.org/downloads/
428[Visual C++ Build Tools]: https://visualstudio.microsoft.com/visual-cpp-build-tools/
429[Visual Studio 2015 Update 3]: https://www.visualstudio.com/vs/older-downloads/
430[Visual Studio 2017]: https://www.visualstudio.com/downloads/
431[Git for Windows]: http://git-scm.com/download/win
432