lines(
			"#ifdef A",
			"#ifdef B",
			"#define C 1234",
			"#else",
			"#define C 5678",
			"#endif",
			"#endif",
			"C",
		),
		"C.\n",
	},
	{
		"nested #define",
		lines(
			"#define A #define B THIS",
			"A",
			"B",
		),
		"THIS.\n",
	},
	{
		"nested #define with args",
		lines(
			"#define A #define B(x) x",
			"A",
			"B(THIS)",
		),

	// We only get here if defining a macro inside a macro.
	// This imperfect implementation means we cannot tell the difference between
	//	#define A #define B(x) x
	// and
	//	#define A #define B (x) x
	// The first definition of B has an argument, the second doesn't. Because we let
	// text/scanner strip the blanks for us, this is extremely rare, hard to fix, and not worth it.
	return s.pos
}

		Can be repeated to define multiple symbols.
	-I dir1 -I dir2
		Search for #include files in dir1, dir2, etc,
		after consulting $GOROOT/pkg/$GOOS_$GOARCH.
	-S
		Print assembly and machine code.
	-V
		Print assembler version and exit.
	-debug
		Dump instructions as they are parsed.
	-dynlink
		Support references to Go symbols defined in other shared libraries.
	-e

  typedef CFStringRef SecKeyAlgorithm;
  static CFDataRef SecKeyCreateSignature(SecKeyRef key, SecKeyAlgorithm algorithm, CFDataRef dataToSign, CFErrorRef *error){return NULL;}
  #define kSecKeyAlgorithmECDSASignatureDigestX962SHA1 foo()
  static SecKeyAlgorithm foo(void){return NULL;}
#endif
*/
import "C"
import "testing"

func f1() {

				// are in hex and half are in whatever the #define used.
				n.Const = fmt.Sprintf("%#x", i)
			} else if n.Define[0] == '\'' {
				if _, err := parser.ParseExpr(n.Define); err == nil {
					n.Kind = "iconst"
					n.Const = n.Define
				}
			} else if n.Define[0] == '"' {
				if _, err := parser.ParseExpr(n.Define); err == nil {
					n.Kind = "sconst"
					n.Const = n.Define
				}
			}

			if n.IsConst() {

	return Token{ScanToken: token, text: text}
}

func (l Token) String() string {
	return l.text
}

// A Macro represents the definition of a #defined macro.
type Macro struct {
	name   string   // The #define name.
	args   []string // Formal arguments.
	tokens []Token  // Body of macro.
}

// Tokenize turns a string into a list of Tokens; used to parse the -D flag and in tests.

		switch in.Stack.Text() {
		case "else", "endif", "ifdef", "ifndef", "line":
			// Press on.
		default:
			return false
		}
	}
	switch in.Stack.Text() {
	case "define":
		in.define()
	case "else":
		in.else_()
	case "endif":
		in.endif()
	case "ifdef":
		in.ifdef(true)
	case "ifndef":
		in.ifdef(false)
	case "include":
		in.include()
	case "line":

	attempts := 1000
	threads := 4

	// Restrict the number of attempts based on RLIMIT_NPROC.
	// Tediously, RLIMIT_NPROC was left out of the syscall package,
	// probably because it is not in POSIX.1, so we define it here.
	// It is not defined on Solaris.
	var nproc int
	setNproc := true
	switch runtime.GOOS {
	default:
		setNproc = false
	case "aix":
		nproc = 9
	case "linux":
		nproc = 6

		return true
	}
	return false
}

// MCR is not defined by the obj/arm; instead we define it privately here.
// It is encoded as an MRC with a bit inside the instruction word,
// passed to arch.ARMMRCOffset.
const aMCR = arm.ALAST + 1

// IsARMMRC reports whether the op (as defined by an arm.A* constant) is
// MRC or MCR.
func IsARMMRC(op obj.As) bool {
	switch op {

explicitly in Go to pointers to arrays, as they do (implicitly) in C.

Garbage collection is the big problem.  It is fine for the Go world to
have pointers into the C world and to free those pointers when they
are no longer needed.  To help, the Go code can define Go objects
holding the C pointers and use runtime.SetFinalizer on those Go objects.

It is much more difficult for the C world to have pointers into the Go