T) { slice := make([]int, 0, 2) slice = append(slice, 1) ptr := unsafe.Pointer(&slice) opt := (*[3]int)(ptr) fmt.Println("array addr: ", opt[0]) slice = append(slice, 2) ptr = unsafe.Pointer(&slice) opt = (*[3]int)(ptr) fmt.Println("array addr: ", opt[0])...
funcprintslice(nstring,s*[]string){typeSliceStructstruct{ptruintptrlenuint64capuint64}p:=(*SliceStruct)(unsafe.Pointer(s));ifn=="s1"{p.cap=2// rewrite cap to 2 for s1 slice by force}fmt.Printf("%s: p=%p,ptr=0x%x,len=%d,cap=%d,val=%v\n",n,p,p.ptr,p.len,p.cap,s)} 再...
slice只是一个结构体，里面存了底层数组的ptr，cap以及本身的len，底层数组重新分配地址只是改变了slice...
map, or chan (only). Like new, the first argument is a type, not a// value. Unlike new, make's return type is the same as the type of its// argument, not a pointer to it. The specification of the result depends on// the type:// Slice: The size specifies the length. The ...
而golang也有这样的划分,基本类型(Golang学习系列第二天已学过)和派生类型(不叫引用类型),派生类型有以下几种:数组类型、切片类型、Map类型、结构体类型(struct)、指针类型(Pointer)、函数类型、接口类型(interface)、Channel 类型。 1. 数组类型 数组是具有相同数据类型的元素序列。 数组在声明中定义了固定的长度,...
// append should not create a slice with nil pointer but non-zero len. // We assume that append doesn't need to preserve old.array in this case. return slice{unsafe.Pointer(&zerobase), old.len, cap} }newcap := old.cap doublecap := newcap + newcapif...
fmt.Println(slice4 != nil) // true 1. 2. 3. 4. 5. 内置函数的len和cap函数分别返回slice的长度和容量 内置函数append进行添加操作 slice6 := []int{1,3,7,5,2,3,4} slice7 := append(slice6,0) slice8 := append(slice7,9,8) ...
)func(v Vertex)Abs()float64{return math.Sqrt(v.X*v.X + v.Y*v.Y)}// Call methodv.Abs()// For mutating methods, you need to use a pointer (see below) to the Struct// as the type. With this, the struct value is not copied for the method call.func(v *Vertex) add(n float...
type slice struct { array unsafe.Pointer // 指针, array指针指向底层数组 len int // 长度 cap int // 容量 } // A notInHeapSlice is a slice backed by runtime/internal/sys.NotInHeap memory. // notInHeapSlice是由runtime/internal/sys.NotInHeap内存支持的切片。
that append doesn't need to preserve old.array in this case. return slice{unsafe.Pointer(&...