or misaligned data, are omitted in the Go struct, replaced by
appropriate padding to reach the next field or the end of the struct.

The standard C numeric types are available under the names
C.char, C.schar (signed char), C.uchar (unsigned char),
C.short, C.ushort (unsigned short), C.int, C.uint (unsigned int),
C.long, C.ulong (unsigned long), C.longlong (long long),
C.ulonglong (unsigned long long), C.float, C.double,

extern void crosscall2(void (*fn)(void *, int), void *, int);
extern void _cgo_panic(void *, int);
extern void _cgo_allocate(void *, int);

void
callPanic(void)
{
	struct { const char *p; } a;
	a.p = "panic from C";
	crosscall2(_cgo_panic, &a, sizeof a);
	*(int*)1 = 1;

%{
#include <stdio.h>
#include <stdlib.h>
%}

%typemap(gotype) const char * "string"
%typemap(in) const char * %{
	$1 = malloc($input.n + 1);
	memcpy($1, $input.p, $input.n);
	$1[$input.n] = '\0';
%}
%typemap(freearg) const char * %{
	free($1);
%}

FILE *fopen(const char *name, const char *mode);
int fclose(FILE *);

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

#include <string.h>

#include "_cgo_export.h"

void
callback(void *f)
{
	// use some stack space
	volatile char data[64*1024];

	data[0] = 0;
	goCallback(f);
        data[sizeof(data)-1] = 0;
}

void
callGoFoo(void)
{
	extern void goFoo(void);
	goFoo();
}

void
IntoC(void)
{
	BackIntoGo();

//go:build gccgo

#include "_cgo_export.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

/* Test calling panic from C.  This is what SWIG does.  */

extern void _cgo_panic(const char *);
extern void *_cgo_allocate(size_t);

void
callPanic(void)
{
	_cgo_panic("panic from C");

	{"long\u0250string\u0250with\u0250nonascii\u2C6Fchars", []byte("LONG\u2C6FSTRING\u2C6FWITH\u2C6FNONASCII\u2C6FCHARS")},
	{"\u0250\u0250\u0250\u0250\u0250", []byte("\u2C6F\u2C6F\u2C6F\u2C6F\u2C6F")}, // grows one byte per char
	{"a\u0080\U0010FFFF", []byte("A\u0080\U0010FFFF")},                           // test utf8.RuneSelf and utf8.MaxRune
}

var lowerTests = []StringTest{
	{"", []byte("")},
	{"abc", []byte("abc")},

var debugDefine = flag.Bool("debug-define", false, "print relevant #defines")
var debugGcc = flag.Bool("debug-gcc", false, "print gcc invocations")

var nameToC = map[string]string{
	"schar":         "signed char",
	"uchar":         "unsigned char",
	"ushort":        "unsigned short",
	"uint":          "unsigned int",
	"ulong":         "unsigned long",
	"longlong":      "long long",
	"ulonglong":     "unsigned long long",

<p>
All other sequences starting with a backslash are illegal inside rune literals.
</p>
<pre class="ebnf">
rune_lit         = "'" ( unicode_value | byte_value ) "'" .
unicode_value    = unicode_char | little_u_value | big_u_value | escaped_char .
byte_value       = octal_byte_value | hex_byte_value .
octal_byte_value = `\` octal_digit octal_digit octal_digit .
hex_byte_value   = `\` "x" hex_digit hex_digit .

	switch t {
	case scanner.EOF:
		return "EOF"
	case scanner.Ident:
		return "identifier"
	case scanner.Int:
		return "integer constant"
	case scanner.Float:
		return "float constant"
	case scanner.Char:
		return "rune constant"
	case scanner.String:
		return "string constant"
	case scanner.RawString:
		return "raw string constant"
	case scanner.Comment:
		return "comment"
	default:

		Mode:   0755 | fs.ModeSymlink,
	},
	{
		Name:   "device",
		Data:   []byte("device file"),
		Method: Deflate,
		Mode:   0755 | fs.ModeDevice,
	},
	{
		Name:   "chardevice",
		Data:   []byte("char device file"),
		Method: Deflate,
		Mode:   0755 | fs.ModeDevice | fs.ModeCharDevice,
	},
}

func TestWriter(t *testing.T) {
	largeData := make([]byte, 1<<17)
	if _, err := rand.Read(largeData); err != nil {