luaposix Files

Lua bindings for POSIX

I am happy to announce release 38 of luaposix.

luaposix's home page is at https://github.com/luaposix/luaposix/

Noteworthy changes in release 38 (2026-10-25) [stable]

New Features

• New posix.time.tzset, to apply a change of the TZ environment variable, as in tzset(3).

• The flags argument of posix.glob.glob is optional, and defaults to 0, as does the pattern to *.

• posix.unistd.getopt returns the option character at fault, in place of the always nil argument, when it returns ? or : for an unrecognized option or a missing argument.

• New posix.unistd.exece, to execute a program with a specified environment, as in execve(2).

• Support for XSI extensions WIFCONTINUED and WCONTINUED in posix.sys.wait.

Bugs Fixed

• Integer fields of tables passed to functions, such as tv_sec and tv_nsec of posix.time.nanosleep, truncate a float towards zero, as they always have in Lua 5.1, 5.2 and LuaJIT, rather than becoming 0 in Lua 5.3 and later.

• The opterr argument of posix.unistd.getopt is documented as what it is, a flag that makes getopt print diagnostics to stderr, not the index of an option with an error, and its usage example runs.

• The usage examples of posix.fcntl.fcntl, posix.fcntl.open and posix.sys.stat.chmod run: they named the wrong module for fcntl, F_GETFL, S_IRWXU and S_IRGRP, and called bit.bor without saying where it comes from.

• The LDoc reference of posix.grp.getgrgid, posix.grp.getgrnam, posix.pwd.getpwnam and posix.pwd.getpwuid says that they return just nil, not an error message, when the group or user does not exist.

• The msqid argument of posix.sys.msg.msgctl, the values to set with IPC_SET, is in the LDoc reference, where its documentation had been left out.

Incompatible Changes

• luaposix is built from the build table of its rockspec, by the luarocks-build-luke LuaRocks build backend, which LuaRocks installs for the build, so there is no build-aux/luke build to run, and no build without LuaRocks. The rock does not build LDocs, which luke release builds and commits.

• The undocumented posix.deprecated module is gone, along with the legacy APIs it added to the posix module in place of the submodule functions of the same names, which were kept for compatibility with luaposix 32 and earlier. Calling one of them from the posix module raises an error naming its replacement:

  Removed	Use instead
  bind	posix.sys.socket.bind
  clock_getres	posix.time.clock_getres
  clock_gettime	posix.time.clock_gettime
  connect	posix.sys.socket.connect
  exec	posix.unistd.exec
  execp	posix.unistd.execp
  fadvise	posix.fcntl.posix_fadvise
  fnmatch	posix.fnmatch.fnmatch
  getgroup	posix.grp.getgrgid or posix.grp.getgrnam
  getpasswd	posix.pwd.getpwuid or posix.pwd.getpwnam
  getpid	posix.unistd.getpid
  getrlimit	posix.sys.resource.getrlimit
  gettimeofday	posix.sys.time.gettimeofday
  gmtime	posix.time.gmtime
  hostid	posix.unistd.gethostid
  isgraph	posix.ctype.isgraph
  isprint	posix.ctype.isprint
  localtime	posix.time.localtime
  mktime	posix.time.mktime
  nanosleep	posix.time.nanosleep
  openlog	posix.syslog.openlog
  pathconf	posix.unistd.pathconf
  setrlimit	posix.sys.resource.setrlimit
  stat	posix.sys.stat.lstat
  statvfs	posix.sys.statvfs.statvfs
  strftime	posix.time.strftime
  strptime	posix.time.strptime
  sysconf	posix.unistd.sysconf
  times	posix.sys.times.times
  uname	posix.sys.utsname.uname

  The replacements take and return the POSIX structures, rather than selecting fields by name; luaposix 37.0 is the last release with the old APIs.

Bugs Fixed

• posix.unistd.getopt accepts any number of arguments. Previously, an argument list longer than about 20 entries could overflow the Lua stack and corrupt memory, and more than 252 failed outright.

• Installing a release rockspec no longer rebuilds the LDocs that the release already includes, so an installed ldoc that fails, as luarocks.org's does with Lua 5.5, no longer breaks the install.

Install it with LuaRocks, using:

luarocks install luaposix 38