hex_float_lit     = "0" ( "x" | "X" ) hex_mantissa hex_exponent .
hex_mantissa      = [ "_" ] hex_digits "." [ hex_digits ] |
                    [ "_" ] hex_digits |
                    "." hex_digits .
hex_exponent      = ( "p" | "P" ) [ "+" | "-" ] decimal_digits .
</pre>

<pre>
0.
72.40
072.40       // == 72.40
2.71828
1.e+0
6.67428e-11
1E6
.25
.12345E+5

// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package cgotest

/*
void callback(void *f);
void callGoFoo(void);
void callGoStackCheck(void);
void callPanic(void);
int callGoReturnVal(void);
int returnAfterGrow(void);
int returnAfterGrowFromGo(void);
void callGoWithString(void);
*/
import "C"

import (
	"path"