Jonathan Amsterdam <******@****.***> 1705947607 -0500

Jonathan Amsterdam <******@****.***> 1705624488 -0500

    > cd doc
    > rm -r next/*
    > cp -r initial/* next

Then edit `next/1-intro.md` to refer to the next version.

To prepare the release notes for a release, run `golang.org/x/build/cmd/relnote generate`.

layout: article
---

<!--
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.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.
If code depends on buggy (including insecure) behavior,

code generated for gcc. The build process links this stub, along with
_cgo_export.c and *.cgo2.c, into a dynamic executable and then lets
cgo examine the executable. Cgo records the list of shared library
references and resolved names and writes them into a new file
_cgo_import.go, which looks like:

	//go:cgo_dynamic_linker "/lib64/ld-linux-x86-64.so.2"

	if err != nil {
		if list, ok := err.(scanner.ErrorList); ok {
			// If err is a scanner.ErrorList, its String will print just
			// the first error and then (+n more errors).
			// Instead, turn it into a new Error that will return
			// details for all the errors.
			for _, e := range list {
				fmt.Fprintln(os.Stderr, e)
			}
			os.Exit(2)
		}
		fatalf("parsing %s: %s", name, err)
	}
	return ast1
}

	check(t, "NewBuffer", buf, testString)
}

func TestNewBufferString(t *testing.T) {
	buf := NewBufferString(testString)
	check(t, "NewBufferString", buf, testString)
}

// Empty buf through repeated reads into fub.
// The initial contents of buf corresponds to the string s.
func empty(t *testing.T, testname string, buf *Buffer, s string, fub []byte) {
	check(t, testname+" (empty 1)", buf, s)

	for {

	VADDPD 8128(DX), Z28, Z29       // 62619d40586a7f
	VADDPD 8128(DX)(AX*2), Z0, Z29  // 6261fd48586c427f
	VADDPD 8128(DX)(AX*2), Z29, Z1  // 62f19540584c427f
	// EVEX: compressed displacement that does not fit into 8bits.
	VADDPD 2048(DX), X29, X0        // 62f19500588200080000
	VADDPD 2048(DX), X1, X29        // 6261f50858aa00080000
	VADDPD 2048(DX), X29, X28       // 6261950058a200080000

	"unsafe"
)

// Pass a func value from nestedCall to goCallback using an integer token.
var callbackMutex sync.Mutex
var callbackToken int
var callbackFuncs = make(map[int]func())

// nestedCall calls into C, back into Go, and finally to f.
func nestedCall(f func()) {
	// callback(x) calls goCallback(x)
	callbackMutex.Lock()
	callbackToken++
	i := callbackToken
	callbackFuncs[i] = f
	callbackMutex.Unlock()

carriage returns (U+000D), and newlines (U+000A),
is ignored except as it separates tokens
that would otherwise combine into a single token. Also, a newline or end of file
may trigger the insertion of a <a href="#Semicolons">semicolon</a>.
While breaking the input into tokens,
the next token is the longest sequence of characters that form a
valid token.
</p>

<h3 id="Semicolons">Semicolons</h3>

<p>