// Copyright 2009 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. /* The unsafe package contains operations that step around the type safety of Go programs. */ package unsafe // ArbitraryType is here for the purposes of documentation only and is not actually // part of the unsafe package. It represents the type of an arbitrary Go expression. type ArbitraryType int // Pointer represents a pointer to an arbitrary type. There are three special operations // available for type Pointer that are not available for other types. // 1) A pointer value of any type can be converted to a Pointer. // 2) A uintptr can be converted to a Pointer. // 3) A Pointer can be converted to a uintptr. // Pointer therefore allows a program to defeat the type system and read and write // arbitrary memory. It should be used with extreme care. type Pointer *ArbitraryType // Sizeof returns the size in bytes occupied by the value v. The size is that of the // "top level" of the value only. For instance, if v is a slice, it returns the size of // the slice descriptor, not the size of the memory referenced by the slice. func Sizeof(v ArbitraryType) int // Offsetof returns the offset within the struct of the field represented by v, // which must be of the form struct_value.field. In other words, it returns the // number of bytes between the start of the struct and the start of the field. func Offsetof(v ArbitraryType) int // Alignof returns the alignment of the value v. It is the minimum value m such // that the address of a variable with the type of v will always always be zero mod m. // If v is of the form obj.f, it returns the alignment of field f within struct object obj. func Alignof(v ArbitraryType) int // Typeof returns the type of an interface value, a runtime.Type. func Typeof(i interface{}) (typ interface{}) // Reflect unpacks an interface value into its type and the address of a copy of the // internal value. func Reflect(i interface{}) (typ interface{}, addr uintptr) // Unreflect inverts Reflect: Given a type and a pointer, it returns an empty interface value // with those contents. func Unreflect(typ interface{}, addr uintptr) (ret interface{})