# 线程处理

When using timers or infinite statements such as `while(true)` or `wait` it is important to use `thread` before the function in order to prevent crashes or freezes.

## What is `thread`?

The `thread` term is used to tell squirrel to run the following function **separately** from the rest of the game, while in a simple scripts code is run sequentially(line 1,2,3 etc) if a line of code would last forever or need to function in parallel to normal gameplay, such as a `wait` command, it is important to use `thread` or the game will get stuck processing that line indefinitely and will not move to the next lines, causing crashes or freezes.

## How do i use `thread`?

Using thread is fairly simple, if we have a function called `delayannouncement` that chooses one player as "it" 10 seconds after spawning we cannot use this function on its own, instead calling it with a thread by simply calling

`thread delayannouncement()`

The same applies to a `while(true)` function, for example `almostover` a function that checks every 5 seconds to see if the game has 2 or less minutes left and announces it if so.

`thread almostover()`

| Example Script                                                                                                    |
| ----------------------------------------------------------------------------------------------------------------- |
| lets try implement both of our scripts from the previous 2 sections, as well as a callback to trigger the script. |

First, lets add our callback to the gamemodes core function.

```cpp
global function GamemodeTag_Init


void function GamemodeTag_Init(){
 AddCallback_GameStateEnter( eGameState.Playing, MatchStart )
}
```

Then lets define the function matchstart and have it simply thread our two important functions.

```cpp
void Matchstart{
 thread delayannouncement()
 thread almostover()
}
```

This script waits 10 seconds, picks a player and announces that player as "it" however being `it` currently does nothing, we will define that later.

```cpp
void delayannouncement(){
 wait 10.0 
 string chosenplayer = GetPlayerArray()[RandomInt(GetPlayerArray().len())]
 string message = chosenplayer + " is it!"
 foreach ( entity player in GetPlayerArray() )
     SendHudMessage( player, message, -1, 0.4, 255, 0, 0, 0, 0, 3, 0.15 )
}
```

This function will now repeat endlessly, waiting 5 seconds before each repeat. make sure to add a `return` or `break` statement to prevent the message looping every 5 seconds after, unless you want that

```cpp
 void almostover(){
  while(true){
    if(GameTime_TimeLeftSeconds() < 120){
      foreach ( entity player in GetPlayerArray() )
	      SendHudMessage( player, "Two minutes left!", -1, 0.4, 255, 0, 0, 0, 0, 3, 0.15 )
        break
      }
    wait 5.0
   }
 }
```

You have now created and threaded both functions.