// compile // Copyright 2023 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package main import ( "fmt" "reflect" "unsafe" ) var slice = []byte{'H', 'e', 'l', 'l', 'o', ','} func main() { ptr := uintptr(unsafe.Pointer(&slice)) + 100 header := (*reflect.SliceHeader)(unsafe.Pointer(ptr)) header.Data += 1 fmt.Printf("%d %d\n", cap(slice), header.Cap) }