# 逃逸闭包

当一个闭包作为参数传到一个函数中，但是**这个闭包在函数返回之后才被执行**，我们称**该闭包从函数中逃逸**。

当你定义接受闭包作为参数的函数时，你可以在参数名之前标注 `@escaping`，用来指明这个闭包是允许“逃逸”出这个函数的。

```swift
var completionHandlers: [() -> Void] = []

// @escaping 将在该函数返回后才调用
func someFunctionWithEscapingClosure(completionHandler: @escaping () -> Void) {
    completionHandlers.append(completionHandler)
}
```


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