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authorRob Pike <r@golang.org>2009-06-09 09:53:44 -0700
committerRob Pike <r@golang.org>2009-06-09 09:53:44 -0700
commit7249ea4df2b4f12a4e7ed446f270cea87e4ffd34 (patch)
tree7032a11d0cac2ae4d3e90f7a189b575b5a50f848 /src/pkg/unsafe
parentacf6ef7a82b3fe61516a1bac4563706552bdf078 (diff)
downloadgolang-7249ea4df2b4f12a4e7ed446f270cea87e4ffd34.tar.gz
mv src/lib to src/pkg
tests: all.bash passes, gobuild still works, godoc still works. R=rsc OCL=30096 CL=30102
Diffstat (limited to 'src/pkg/unsafe')
-rw-r--r--src/pkg/unsafe/unsafe.go44
1 files changed, 44 insertions, 0 deletions
diff --git a/src/pkg/unsafe/unsafe.go b/src/pkg/unsafe/unsafe.go
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+// 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
+
+// Reflect unpacks an interface value into its internal value word and its type string.
+// The boolean indir is true if the value is a pointer to the real value.
+func Reflect(i interface {}) (value uint64, typestring string, indir bool)
+
+// Unreflect inverts Reflect: Given a value word, a type string, and the indirect bit,
+// it returns an empty interface value with those contents.
+func Unreflect(value uint64, typestring string, indir bool) (ret interface {})