How works love.threads?

[NoAim91]

Hey, the love.thread thing really need a bit more description at the wiki. I like to input a variable in the thread and get a return after a function call. In this case I put 10 in, the function should add 3 and the return should be 13. But the function inside the thread doesn´t get called. and in generell I have no clue what is going on.

main.lua

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function love.load()
  t  = love.thread.newThread("thread.lua")
  c1 = love.thread.newChannel()

  
  input = 10
 
  t:start(c1:push(input))
  
  table = c1:demand()
  print(table)
end

thread.lua

Code: Select all

function test(input)
  a = 3
  a = a + input
  print(a)
  return a
end

input = c1:demand()
c1:push(test(input))

[zorg]

Anything you pass into Thread:start will be available as a "file-level" vararg that you can access by doing this:

Code: Select all

local stuff = {...}

for example; you can also use the select function too.

Haven't tested the following, but it may or may not work:

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-- main.lua
function love.load()
  t  = love.thread.newThread("thread.lua")
  c1 = love.thread.newChannel()

  
  input = 10
 
  t:start(c1)
  c1:push(input)
  table = c1:demand()
  print(table)
end

Code: Select all

--thread.lua
local c1 = {...}[1]

function test(input)
  a = 3
  a = a + input
  print(a)
  return a
end

input = c1:demand()
c1:push(test(input))

[NoAim91]

@zorg: nope, doesn´t work.

Maybe I don´t need channels for this.

I tryed this

Code: Select all

--main.lua
function love.load()
  t     = love.thread.newThread("thread.lua")

  input = 10
  
  output = t:start( input )

  print(output)
  
end

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--thread.lua
local input = input

function test(input)
  a = 3
  a = a + input
  print(a)
  return a
end

test(input)

and this did not work.

print(output) --> true
print(a) --> doesn´t print anything

[Nixola]

Unless you define the love.threaderror callback or call Thread:getError you won't see any errors your thread code throws.

[NoAim91]

Code: Select all

local input = input

function test(input)
  a = input
  a = a + 3
  print(a)
  return a
end

test(input)

Thread error!
thread.lua:5: attempt to perform arithmetic on global 'a' (a nil value)

line 5 is a = a + 3

so what?! define a = input is fine but after that a is unknown?! o.O

[bartbes]

Yes, because input is nil, change your first line to

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local input = ...

[NoAim91]

thank you! :-)

Ok, now how I get the resault ( a ) out of the thread? XD

[bartbes]

The easiest way is using a channel, so if we take your initial code again...

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-- main.lua
function love.load()
  t  = love.thread.newThread("thread.lua")
  c1 = love.thread.newChannel()

  
  input = 10
  c1:push(input)
  t:start(c1)
  
  table = c1:demand()
  print(table)
end

-- thread.lua
local c1 = ...

function test(input)
  a = 3
  a = a + input
  print(a)
  return a
end

input = c1:demand()
c1:push(test(input))

Of course you probably don't want to use threads for this, but it should work.

[NoAim91]

@bartbes: this code doesn´t work :-/

I changed something that it work, but it is not finaly right:

Code: Select all

 
main.lua

function love.load()
  t     = love.thread.newThread("thread.lua")
  c1    = love.thread.newChannel()

  input = 10
  
  c1:push(input)
  t:start(c1)

end

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thread.lua

local c1 = ...
input = c1:demand()
print("thread/ input: "..input) -- print 10

function test(input)
  a = input
  a = a + 3
  print("thread/ a: "..a) -- print 13
  return a
end

c1:push(test(input))

and the strange thing is, when I write this:

Code: Select all

function love.load()
  t     = love.thread.newThread("thread.lua")
  c1    = love.thread.newChannel()

  input = 10
  
  c1:push(input)
  t:start(c1)
  
  output = c1:demand()
  print("main/ output: "..output) --print 10
  
end

it only print 10 ... and nothing from the thread ... and the thread gives no error

[zorg]

So your issue is that the print command doesn't work in the thread? Because it seems like the thread did return 10 to the main thread, and it was printed...