luaposix 36.2.1

• Index

Contents

• Functions
• Tables
• Constants

Modules

• posix
• posix.ctype
• posix.dirent
• posix.errno
• posix.fcntl
• posix.fnmatch
• posix.glob
• posix.grp
• posix.libgen
• posix.poll
• posix.pwd
• posix.sched
• posix.signal
• posix.stdio
• posix.stdlib
• posix.sys.msg
• posix.sys.resource
• posix.sys.socket
• posix.sys.stat
• posix.sys.statvfs
• posix.sys.time
• posix.sys.times
• posix.sys.utsname
• posix.sys.wait
• posix.syslog
• posix.termio
• posix.time
• posix.unistd
• posix.utime

Examples

• abstract-ns-client.lua
• abstract-ns-server.lua
• dir.lua
• dup2.lua
• fork.lua
• fork2.lua
• getopt.lua
• glob.lua
• limit.lua
• lock.lua
• netlink-uevent.lua
• packet-socket.lua
• ping.lua
• poll.lua
• rt_sched.lua
• signal.lua
• socket.lua
• termios.lua
• tree.lua

Module posix.time

Time and Clock Functions.

Functions

clock_getres (clk)	Find the precision of a clock.
clock_gettime (clk)	Read a clock.
gmtime (t)	Convert epoch time value to a broken-down UTC time.
localtime (t)	Convert epoch time value to a broken-down local time.
mktime (broken)	Convert a broken-down localtime table into an epoch time.
nanosleep (requested)	Sleep with nanosecond precision.
strftime (format, tm)	Return a time string according to format.
strptime (s, format)	Parse a date string.
time ()	Get current time.

Tables

PosixTimespec	Timespec record.
PosixTm	Datetime record.

Constants

posix.time

Standard constants.

Functions

clock_getres (clk)

Find the precision of a clock.

Parameters:

• clk int name of clock, one of CLOCK_REALTIME, CLOCK_PROCESS_CPUTIME_ID, CLOCK_MONOTONIC or CLOCK_THREAD_CPUTIME_ID

Returns:

PosixTimespec resolution of clk, if successful

Or

1. nil
2. string error message
3. int errnum

See also:

clock_getres(3)

clock_gettime (clk)

Read a clock.

Parameters:

• clk int name of clock, one of CLOCK_REALTIME, CLOCK_PROCESS_CPUTIME_ID, CLOCK_MONOTONIC or CLOCK_THREAD_CPUTIME_ID

Returns:

PosixTimespec current value of clk, if successful

Or

1. nil
2. string error message
3. int errnum

See also:

clock_gettime(3)

gmtime (t)

Convert epoch time value to a broken-down UTC time.

Parameters:

• t int seconds since epoch

Returns:

PosixTm broken-down time, if successful

Or

1. nil
2. string error message
3. int errnum

See also:

gmtime(3)

localtime (t)

Convert epoch time value to a broken-down local time.

Parameters:

• t int seconds since epoch

Returns:

PosixTm broken-down time, if successful

Or

1. nil
2. string error message
3. int errnum

See also:

• localtime(3)
• mktime

mktime (broken)

Convert a broken-down localtime table into an epoch time.

Parameters:

• broken PosixTm -down localtime

Returns:

int seconds since epoch

See also:

• mktime(3)
• localtime

nanosleep (requested)

Sleep with nanosecond precision.

Parameters:

• requested PosixTimespec sleep time

Returns:

int 0 if requested time has elapsed, if successful

Or

1. nil
2. string error message
3. int errnum
4. PosixTimespec unslept time remaining, if interrupted

See also:

• nanosleep(2)
• posix.unistd.sleep

strftime (format, tm)

Return a time string according to format. Note that if your host POSIX library provides a strftime that assumes the local timezone, %z will always print the local UTC offset, regardless of the tm_gmoffset field value passed in.

Parameters:

• format string specifier with % place-holders
• tm PosixTm broken-down local time

Returns:

string format with place-holders plugged with tm values

See also:

strftime(3)

strptime (s, format)

Parse a date string.

Parameters:

• s string
• format string same as for strftime

Returns:

1. PosixTm broken-down local time
2. int next index of first character not parsed as part of the date, if successful

Or

nil

See also:

strptime(3)

Usage:

posix.strptime('20','%d').monthday == 20

time ()

Get current time.

Returns:

int time in seconds since epoch, if successful

Or

1. nil
2. string error message
3. int errnum

See also:

time(2)

Tables

PosixTimespec

Timespec record.

Fields:

• tv_sec int seconds
• tv_nsec int nanoseconds

See also:

posix.sys.time.PosixTimeval

PosixTm

Datetime record.

Fields:

• tm_sec int second [0,60]
• tm_min int minute [0,59]
• tm_hour int hour [0,23]
• tm_mday int day of month [1, 31]
• tm_mon int month of year [0,11]
• tm_year int years since 1900
• tm_wday int day of week [0=Sunday,6]
• tm_yday int day of year [0,365[
• tm_isdst int 0 if daylight savings time is not in effect

Constants

posix.time

Standard constants. Any constants not available in the underlying system will be nil valued.

Fields:

• CLOCK_MONOTONIC int the identifier for the system-wide monotonic clock
• CLOCK_PROCESS_CPUTIME_ID int the identifier for the current process CPU-time clock
• CLOCK_REALTIME int the identifier for the system-wide realtime clock
• CLOCK_THREAD_CPUTIME_ID int the identifier for the current thread CPU-time clock

Usage:

-- Print posix.time constants supported on this host.
for name, value in pairs (require "posix.time") do
  if type (value) == "number" then
    print (name, value)
   end
end