// 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. /* Package unsafe contains operations that step around the type safety of Go programs. Packages that import unsafe may be non-portable and are not protected by the Go 1 compatibility guidelines. */ 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 four 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 Pointer can be converted to a pointer value of any type. // 3) A uintptr can be converted to a Pointer. // 4) 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 takes an expression x of any type and returns the size in bytes // of a hypothetical variable v as if v was declared via var v = x. // The size does not include any memory possibly referenced by x. // For instance, if x is a slice, Sizeof returns the size of the slice // descriptor, not the size of the memory referenced by the slice. func Sizeof(x ArbitraryType) uintptr // Offsetof returns the offset within the struct of the field represented by x, // which must be of the form structValue.field. In other words, it returns the // number of bytes between the start of the struct and the start of the field. func Offsetof(x ArbitraryType) uintptr // Alignof takes an expression x of any type and returns the alignment // of a hypothetical variable v as if v was declared via var v = x. // It is the largest value m such that the address of v is zero mod m. func Alignof(x ArbitraryType) uintptr