In the absence of data races, Go programs behave as if all the goroutines
were multiplexed onto a single processor.
This property is sometimes referred to as DRF-SC: data-race-free programs
execute in a sequentially consistent manner.
</p>

<p>
While programmers should write Go programs without data races,
there are limitations to what a Go implementation can do in response to a data race.

// and then Reader can be treated as an io.Reader to access the file's data.
type Reader struct {
	r    io.Reader
	pad  int64      // Amount of padding (ignored) after current file entry
	curr fileReader // Reader for current file entry
	blk  block      // Buffer to use as temporary local storage

	// err is a persistent error.

// existing file, such as a binary executable.
// It must be called before any data is written.
func (w *Writer) SetOffset(n int64) {
	if w.cw.count != 0 {
		panic("zip: SetOffset called after data was written")
	}
	w.cw.count = n
}

// Flush flushes any buffered data to the underlying writer.
// Calling Flush is not normally necessary; calling Close is sufficient.
func (w *Writer) Flush() error {

// never both.
//
// The text returned from ReadLine does not include the line end ("\r\n" or "\n").
// No indication or error is given if the input ends without a final line end.
// Calling [Reader.UnreadByte] after ReadLine will always unread the last byte read
// (possibly a character belonging to the line end) even if that byte is not
// part of the line returned by ReadLine.

	for attempt := 0; attempt < 5; attempt++ {
		conn, err := net.DialTimeout("tcp", "localhost:3222", 5*time.Second)
		if err == nil {
			conn.Close()
			return closer, nil
		}
		select {
		case <-time.After(delay):
			delay *= 2
		case err := <-errChan:
			return nil, err
		}
	}
	closer()
	return nil, errors.New("failed to set up idevicedebugserverproxy")
}

	// Determine the package by examining the current working
	// directory, which will look something like
	// "$GOROOT/src/mime/multipart" or "$GOPATH/src/golang.org/x/mobile".
	// We extract everything after the $GOROOT or $GOPATH to run on the
	// same relative directory on the target device.
	importPath, isStd, modPath, modDir, err := pkgPath()
	if err != nil {
		return 0, err
	}
	var deviceCwd string
	if isStd {

		lines(
			"#define A 1\\",
			"\t2\\",
			"\t3",
			"before",
			"A",
			"after",
		),
		"before.\n.1.\n.2.\n.3.\n.after.\n",
	},
	{
		"multiline macro with arguments",
		lines(
			"#define A(a, b, c) a\\",
			"\tb\\",
			"\tc",
			"before",
			"A(1, 2, 3)",
			"after",
		),
		"before.\n.1.\n.2.\n.3.\n.after.\n",
	},
	{
		"LOAD macro",
		lines(
			"#define LOAD(off, reg) \\",

func testThreadLock(t *testing.T) {
	stop := make(chan int)
	go func() {
		// We need the G continue running,
		// so the M has a chance to run this G.
		for {
			select {
			case <-stop:
				return
			case <-time.After(time.Millisecond * 100):
			}
		}
	}()
	defer close(stop)

	for i := 0; i < 1000; i++ {
		if !C.Ctid() {
			t.Fatalf("cgo has not locked OS thread")
		}
	}

	MOVL 2147483648(AX), AX  // 8b8000000080
	MOVL -2147483648(AX), AX // 8b8000000080
	ADDL 2147483648(AX), AX  // 038000000080
	ADDL -2147483648(AX), AX // 038000000080
	// Make sure MOV CR/DR continues to work after changing its movtabs.
	MOVL CR0, AX // 0f20c0
	MOVL CR0, DX // 0f20c2
	MOVL CR4, DI // 0f20e7
	MOVL AX, CR0 // 0f22c0
	MOVL DX, CR0 // 0f22c2
	MOVL DI, CR4 // 0f22e7
	MOVL DR0, AX // 0f21c0
	MOVL DR6, DX // 0f21f2

			hexByLine[fmt.Sprintf("%s:%d", input, lineno)] = hexes
		}

		// Canonicalize spacing in printed form.
		// First field is opcode, then tab, then arguments separated by spaces.
		// Canonicalize spaces after commas first.
		// Comma to separate argument gets a space; comma within does not.
		var buf []byte
		nest := 0
		for i := 0; i < len(printed); i++ {
			c := printed[i]
			switch c {
			case '{', '[':