Why is my custom lua wait function erroing?

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Hello i got an issue where i'm trying to make a wait function in lua but it's erroring does anyone know why and how to fix this issue thankyou to those who helped :)

Lua

<pre>--  Function for Vanila Lua

local function sleep(seconds)
  local waittime = os.clock() + seconds/10
  repeat until os.clock() > waittime
  return seconds
end

local returnedWait = sleep(seconds)

print(returnedWait)

Error

/usr/bin/lua: main.lua:22: attempt to perform arithmetic on a nil value (local 'seconds')
stack traceback:
	main.lua:22: in local 'sleep'
	main.lua:27: in main chunk
	[C]: in ?

What I have tried:

I have tried to debug the issue google searching and none of that fixed my issue

Posted 2-May-22 6:09am

Anthony Durk

Updated 7-May-22 8:34am

v2

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Comments

Richard MacCutchan 2-May-22 12:17pm

The message is saying that seconds is not defined within the scope of the above code.

Anthony Durk 2-May-22 12:40pm

it works but the problem is in a while loop it's not waiting it's timing out the script

local function wait(seconds)
local waittime = os.clock() + seconds/10
repeat until os.clock() > waittime
return seconds
end

local returnedWait = wait(10)

print(returnedWait)

while true do
wait(10)
print("this is printing every 10 seconds")
end

3 solutions

Solution 1

Look at your code: you do not give a value to the variable seconds when you pass it to your function.
Try this:

Lua

local function sleep(seconds)
  local waittime = os.clock() + seconds/10
  repeat until os.clock() > waittime
  return seconds
end

local returnedWait = sleep(60)

Posted 2-May-22 6:27am

OriginalGriff

Solution 3

You method of waiting is a bad idea.

Lua

--  Function for Vanila Lua

local function sleep(seconds)
  local waittime = os.clock() + seconds/10
  repeat until os.clock() > waittime
  return seconds
end

This code is waiting from the user point of view, but it is continuously running from a hardware point of view, and thus it is hogging resources (on multitasking device, it makes a difference), on calculator, it is draining batteries.

You should study the usage of timers, they allow real sleep of hardware.
Category:timer - Inspired-Lua Wiki[^]
on.timer - Inspired-Lua Wiki[^]
Category:Events - Inspired-Lua Wiki[^]

Posted 7-May-22 8:34am

Patrice T

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CPallini · Accepted Answer · 2022-05-02T07:59:00

From Lua 5.3 Reference Manual[^]:

 os.clock ()

Returns an approximation of the amount in seconds of CPU time used by the program.

It doesn't seem to me the most appropriate function for implementing a delay.
Try

Lua

local function wait(seconds)
  local tend = os.time() + seconds

  while os.time() < tend do
    -- just waste CPU cycles here
  end
  return seconds
end

local returnedWait = wait(10)
print(returnedWait)

while true do
  wait(10)
  print("this is printing every 10 seconds")
end

Please note, in order to obtain tinier time intervals, you have to call underlying OS (specific) functions.