---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

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This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
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## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

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>.
For more information and other documents, see <a href="/">go.dev</a>.
</p>

<p>
Go is a general-purpose language designed with systems programming
in mind. It is strongly typed and garbage-collected and has explicit

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NOTE: In this document and others in this directory, the convention is to
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<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>
Go is a general-purpose language designed with systems programming
in mind. It is strongly typed and garbage-collected and has explicit

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

/*
Package builtin provides documentation for Go's predeclared identifiers.
The items documented here are not actually in package builtin
but their descriptions here allow godoc to present documentation
for the language's special identifiers.
*/
package builtin

import "cmp"

	default:
		return false
	}
	return true
}

// symDefRef scans a line for potential text symbol definitions and
// references and writes symabis information to w.
//
// The symabis format is documented at
// cmd/compile/internal/ssagen.ReadSymABIs.
func (p *Parser) symDefRef(w io.Writer, word string, operands [][]lex.Token) {
	switch word {
	case "TEXT":
		// Defines text symbol in operands[0].

such as those in the <a href="/pkg/sync/"><code>sync</code></a>
and <a href="/pkg/sync/atomic/"><code>sync/atomic</code></a> packages.
</p>

<p>
If you must read the rest of this document to understand the behavior of your program,
you are being too clever.
</p>

<p>
Don't be clever.
</p>

<h3 id="overview">Informal Overview</h3>

<p>