Threads and timers

Scripts must never block the game. Long-running work happens in threads: functions that pause with Wait and continue on a later tick.

CreateThread(function()
  while true do
    Wait(1000) -- pause one second; the game keeps running
    print('tick')
  end
end)

• CreateThread(fn) starts fn on the next tick.
• Wait(ms) pauses the current thread. Wait(0) waits until the next tick.
• SetTimeout(ms, fn) runs fn once after a delay.
• Event handlers run as threads too, so they may call Wait.

Always call Wait in loops

Every time a thread runs, it gets a budget of instructions (50 million by default). A loop without Wait runs out of budget and the runtime stops that run with an error. Other resources keep running.

-- Wrong: never yields
CreateThread(function()
  while true do end
end)

-- Right
CreateThread(function()
  while true do
    Wait(0)
  end
end)

Wait outside a thread

Wait at the top level of a script fails: Wait can only be called inside a thread or event handler. Wrap the code in CreateThread.

Measuring time

GetGameTimer() returns milliseconds since the runtime started:

local started = GetGameTimer()
Wait(250)
print(GetGameTimer() - started) -- about 250

The FiveM names Citizen.CreateThread, Citizen.Wait and Citizen.SetTimeout work as well.