golang new 和make 做了什么

一般 使用的struct 的时候喜欢 new 一下 map chan make一下

new 是一个内置函数 go1.17/src/runtime/malloc.go：1233

func newobject(typ *_type) unsafe.Pointer {
	return mallocgc(typ.size, typ, true)
}

• 主要是 传入一个 type 声明一块内存 并返回类型的 默认值的指针

make 也是内置函数 go1.17/src/runtime/slice.go:83

func makeslice(et *_type, len, cap int) unsafe.Pointer {
	mem, overflow := math.MulUintptr(et.size, uintptr(cap))
	if overflow || mem > maxAlloc || len < 0 || len > cap {
		// NOTE: Produce a 'len out of range' error instead of a
		// 'cap out of range' error when someone does make([]T, bignumber).
		// 'cap out of range' is true too, but since the cap is only being
		// supplied implicitly, saying len is clearer.
		// See golang.org/issue/4085.
		mem, overflow := math.MulUintptr(et.size, uintptr(len))
		if overflow || mem > maxAlloc || len < 0 {
			panicmakeslicelen()
		}
		panicmakeslicecap()
	}

	return mallocgc(mem, et, true)
}

• 也是传入type 和 长度 但是返回的改具体值的

标签：mem,make,cap,len,golang,et,new,type
来源： https://www.cnblogs.com/guanchaoguo/p/16457656.html