<!--{
	"Title": "The Go Programming Language Specification",
	"Subtitle": "Language version go1.22 (April 25, 2024)",
	"Path": "/ref/spec"
}-->

<h2 id="Introduction">Introduction</h2>

<p>
This is the reference manual for the Go programming language.
The pre-Go1.18 version, without generics, can be found
<a href="/doc/go1.17_spec.html">here</a>.
For more information and other documents, see <a href="/">go.dev</a>.
</p>

<p>

	"Subtitle": "Version of Oct 15, 2021",
	"Path": "/ref/spec"
}-->

<h2 id="Introduction">Introduction</h2>

<p>
This is the reference manual for the Go programming language as it was for
language version 1.17, in October 2021, before the introduction of generics.
It is provided for historical interest.
The current reference manual can be found <a href="/doc/go_spec.html">here</a>.

	JCS	2(PC)
	JMP	(AX)(AX*4)
	JCS	2(PC)
	JMP	R13

// LTYPEN spec4	{ outcode($1, &$2); }
	NOP
	NOP	AX
	NOP	foo+4(SB)

// LTYPES spec5	{ outcode($1, &$2); }
	SHLL	CX, R12
	SHLL	CX, foo+4(SB)
	// Old syntax, still accepted:
	SHLL	CX, R11:AX // SHLL CX, AX, R11

// LTYPEM spec6	{ outcode($1, &$2); }
	MOVL	AX, R11
	MOVL	$4, R11
//	MOVL	AX, 0(AX):DS // no longer works - did it ever?

			if !ok {
				ast2.Decls[w] = decl
				w++
				continue
			}
			ws := 0
			for _, spec := range d.Specs {
				s, ok := spec.(*ast.ImportSpec)
				if !ok || s.Path.Value != `"C"` {
					d.Specs[ws] = spec
					ws++
				}
			}
			if ws == 0 {
				continue
			}
			d.Specs = d.Specs[0:ws]
			ast2.Decls[w] = d
			w++
		}
		ast2.Decls = ast2.Decls[0:w]
	} else {

// (due to the printer possibly inserting newlines because of position
// information) operators.
var gofmtLineReplacer = strings.NewReplacer(
	// Want to replace \n without ; after everything from
	// https://golang.org/ref/spec#Operators_and_punctuation
	// EXCEPT ++ -- ) ] }
	"++\n", "++;",
	"--\n", "--;",

	"+\n", "+ ",
	"-\n", "- ",
	"*\n", "* ",
	"/\n", "/ ",
	"%\n", "% ",
	"&\n", "& ",
	"|\n", "| ",

pkg syscall (darwin-386), type Inet4Pktinfo struct, Addr [4]uint8
pkg syscall (darwin-386), type Inet4Pktinfo struct, Ifindex uint32
pkg syscall (darwin-386), type Inet4Pktinfo struct, Spec_dst [4]uint8
pkg syscall (darwin-386), type Termios struct
pkg syscall (darwin-386), type Termios struct, Cc [20]uint8
pkg syscall (darwin-386), type Termios struct, Cflag uint32

	_ = needUSize

	if needCSize || needHeaderOffset {
		return ErrFormat
	}

	return nil
}

func readDataDescriptor(r io.Reader, f *File) error {
	var buf [dataDescriptorLen]byte
	// The spec says: "Although not originally assigned a
	// signature, the value 0x08074b50 has commonly been adopted
	// as a signature value for the data descriptor record.
	// Implementers should be aware that ZIP files may be

    validations:
      required: true

  - type: textarea
    id: language-spec-changes
    attributes:
      label: "Language Spec Changes"
      description: "What would change in the language spec?"
    validations:
      required: false

  - type: textarea
    id: informal-change
    attributes:
      label: "Informal Change"

This behavior can be controlled by the
[`httpmuxgo121` setting](/pkg/net/http/#ServeMux).

Go 1.22 added the [Alias type](/pkg/go/types#Alias) to [go/types](/pkg/go/types)
for the explicit representation of [type aliases](/ref/spec#Type_declarations).
Whether the type checker produces `Alias` types or not is controlled by the
[`gotypesalias` setting](/pkg/go/types#Alias).
For Go 1.22 it defaults to `gotypesalias=0`.

	paxUid      = "uid"
	paxGid      = "gid"
	paxUname    = "uname"
	paxGname    = "gname"
	paxMtime    = "mtime"
	paxAtime    = "atime"
	paxCtime    = "ctime"   // Removed from later revision of PAX spec, but was valid
	paxCharset  = "charset" // Currently unused
	paxComment  = "comment" // Currently unused

	paxSchilyXattr = "SCHILY.xattr."

	// Keywords for GNU sparse files in a PAX extended header.