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By the luaposix project

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This is a POSIX binding for LuaJIT, Lua 5.1, 5.2, 5.3 and 5.4; like most libraries it simply binds to C APIs on the underlying system, so it won't work on non-POSIX systems. However, it does try to detect the level of POSIX conformance of the underlying system and bind only available APIs.

For a while, luaposix contained support for curses functionality too, but now that has its own lcurses repository again, where it is being maintained separately.

luaposix is released under the MIT license (the same license as Lua itsef). There is no warranty.


The simplest and best way to install luaposix is with LuaRocks. To install the latest release (recommended):

    luarocks install luaposix

To install current git master (for testing, before submitting a bug report for example):

    luarocks install

The best way to install without LuaRocks, is to call the bundled build-aux/luke command, as shown in the build section of the included rockspec file, from a freshly cloned working copy.

Note that you'll be responsible for providing dependencies if you choose not to let LuaRocks handle them for you, though you can find a list of minimal dependencies in the rockspec file.

If you are repackaging or redistributing luaposix, it is better to start from a release tarball, because the master development branch is branch is unstable, and sometimes breaks subtly, or does not build at all, or provides experimental new APIs that end up being removed prior to the next official release.

Note that there are full logs of complete builds for every commit in Github Actions, which you can compare with your progress if you get stuck.


The library is split into submodules according to the POSIX header file API declarations, which you can require individually:

    local unistd = require 'posix.unistd'

The authoritative online POSIX reference is published at SUSv3.


The latest release of this library is documented in LDoc. Pre-built HTML files are included in the release, and contain links to the appropriate SUSv3 manual pages.

Example code

See the example program tree.lua, along with the many small examples in the generated documentation and BDD specs/*_spec.yaml.

For a complete application, see the GNU Zile.

Bugs reports and code contributions

These libraries are maintained by their users.

Please make bug reports and suggestions as GitHub issues. Pull requests are especially appreciated.

But first, please check that your issue has not already been reported by someone else, and that it is not already fixed on master in preparation for the next release (See Installation section above for how to temporarily install master with LuaRocks).

There is no strict coding style, but please bear in mind the following points when proposing changes:

  1. Follow existing code. There are a lot of useful patterns and avoided traps there.

  2. 8-character indentation using TABs in C sources; 3-character indentation using SPACEs in Lua sources.

  3. Simple strings are easiest to type using single-quote delimiters saving double-quotes for where a string contains apostrophes.

  4. Save horizontal space by only using SPACEs where the parser requires them.

  5. Use vertical space to separate out compound statements to help the coverage reports discover untested lines.

  6. Prefer explicit string function calls over object methods, to mitigate issues with monkey-patching in caller environment.

  7. No non-POSIX APIs; no platform-specific code. When wrapping APIs introduced in POSIX 2001 or later, add an appropriate #if. If your platform isn't quite POSIX, you may find a gnulib module to bridge the gap. If absolutely necessary, use luke feature tests.

  8. Thin wrappers: although some existing code contradicts this, wrap POSIX APIs in the simplest way possible. If necessary, more convenient wrappers can be added in Lua (posix.lua).