golang defer实现

最新推荐文章于 2025-06-12 01:57:59 发布

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最新推荐文章于 2025-06-12 01:57:59 发布 · 492 阅读

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#golang #开发语言 #后端

本文详细解释了Go语言中defer的关键概念，包括其工作原理（基于链表的执行顺序）、defer结构体的定义以及defer的创建和执行过程。特别关注了如何通过头插法实现先进后出的执行策略。

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derfer : 延迟调用，函数结束返回时执行，多个defer按照先进后出的顺序调用

原理：底层通过链表实现，每次新增的defer调用，通过头插法插入链表；defer执行时，从链表头开始遍历，相当于实现了后加入的defer先执行，先加的defer后执行

defer结构体

type _defer struct {
   
   
	started bool
	heap    bool
	// openDefer indicates that this _defer is for a frame with open-coded
	// defers. We have only one defer record for the entire frame (which may
	// currently have 0, 1, or more defers active).
	openDefer bool
	sp        uintptr // sp at time of defer
	pc        uintptr // pc at time of defer
	fn        func()  // can be nil for open-coded defers
	_panic    *_panic // panic that is running defer
	link      *_defer // next defer on G; can point to either heap or stack!

	// If openDefer is true, the fields below record values about the stack
	// frame and associated function that has the open-coded defer(s). sp
	// above will be the sp for the frame, and pc will be address of the
	// deferreturn call in the function.
	fd   unsafe.Pointer //