dst := float32(src)

var num int = 520
f32 := float32(num)
i64 := int64(num)

dst,ok := src.(int) // 安全类型断言,通过ok判断是否转换成功
dst := src.(int)　  // 非安全类型断言，无法确定是否转换成功

var val interface{} = 123
num,ok := val.(int)
if ok {
    fmt.Printf("%T->%d\n", num, num)
} else {
    fmt.Println("类型不匹配")
}

//类型转换  string to bytes 
func str2bytes(s string) []byte {
    x := (*[2]uintptr)(unsafe.Pointer(&s))
    h := [3]uintptr{x[0], x[1], x[1]}
    return *(*[]byte)(unsafe.Pointer(&h))
}
//类型转换  bytes to string
func bytes2str(b []byte) string {
    return *(*string)(unsafe.Pointer(&b))
}

//interface转为string 
func interface2string(inter interface{}) string {
    tempStr := ""
    switch inter.(type) {
        case string: tempStr = inter.(string) break
        case float64: tempStr = strconv.FormatFloat(inter.(float64), 'f', -1, 64) break
        case int64: tempStr = strconv.FormatInt(inter.(int64), 10) break
        case int: tempStr = strconv.Itoa(inter.(int)) break
	}
    return tempStr
}

//整形转字符串
strconv.Itoa(100)

//该方法的源码是：
//可以看出是FormatInt方法的简单实现。
func Itoa(i int) string {
        return FormatInt(int64(i), 10)
}

//字符串转整形
i, _ := strconv.Atoi("100")

//64位整形转字符串,FormatInt第二个参数表示进制，10表示十进制
var i int64
i = 0x100
strconv.FormatInt(i, 10)


//字节转32位整形
b := []byte{0x00, 0x00, 0x03, 0xe8}
bytesBuffer := bytes.NewBuffer(b)

//其中binary.BigEndian表示字节序，相应的还有little endian。通俗的说法叫大端、小端。
var x int32
binary.Read(bytesBuffer, binary.BigEndian, &x)
fmt.Println(x)

//32位整形转字节
var x int32
x = 106
bytesBuffer := bytes.NewBuffer([]byte{})
binary.Write(bytesBuffer, binary.BigEndian, x)
fmt.Println(bytesBuffer.Bytes())

//字节转字符串
fmt.Println(string([]byte{97, 98, 99, 100}))

//字符串转字节
fmt.Println([]byte("abcd"))

//string-->unicode
func Str2uft16ptr(str string)(p uintptr){//将字符串转为utf16指针
	e:=utf16.Encode([]rune(str))//转成unicode
	e=append(e, uint16(0))//添加末尾的0
	p=uintptr(unsafe.Pointer(&e[0]))//转成指针
	//p=uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(str)))
	return
}

//unicode-->string
func addbuf(buf []uint16,newcap int)(newbuf []uint16){
	newbuf=make([]uint16,newcap)
	copy(newbuf,buf)
	return
}

func Utf16prt2str(p uintptr)(str string){//将utf16指针转为字符串
	len:=0
	buf:=make([]uint16,64)
	for a:=(*(*uint16)(unsafe.Pointer(p)));a!=0;len++{
		if len>=cap(buf){
			buf=addbuf(buf,len*2)
		}
		buf[len]=a
		p+=2//uint16占2字节
		a=(*(*uint16)(unsafe.Pointer(p)))
	}
	str=string(utf16.Decode(buf[:len]))
	return
}

#cgo
char -->  C.char -->  byte
signed char -->  C.schar -->  int8
unsigned char -->  C.uchar -->  uint8
short int -->  C.short -->  int16
short unsigned int -->  C.ushort -->  uint16
int -->  C.int -->  int
unsigned int -->  C.uint -->  uint32
long int -->  C.long -->  int32 or int64
long unsigned int -->  C.ulong -->  uint32 or uint64
long long int -->  C.longlong -->  int64
long long unsigned int -->  C.ulonglong -->  uint64
float -->  C.float -->  float32
double -->  C.double -->  float64
wchar_t -->  C.wchar_t  -->  
void * -> unsafe.Pointer

#window
uint64 //对应SIZE_T
uint32 //对应DWORD

//整型数
//Go->C：
var i int
ci := C.int(i)

//C->Go：
var i C.int
goi := int(i)

//数组和字符串
//Go->C：
var str string
cstr := C.CString(str)

//C->Go：
/*
#include <stdlib.h>
#include <stdio.h>
char foo[] = "hellofoo";
char *bar = "hellobar";
*/
import "C"
import "fmt"

func main() {
    fmt.Printf("%s\n", C.GoString(&C.foo[0]))
    fmt.Printf("%s\n", C.GoString(C.bar))
}

//数组类型转换
/*
#include <stdio.h>
int cIArray[] = {1, 2, 3, 4, 5, 6, 7}; //int
float cFArray[] = {1.011, 2.022, 3.022, 4.023, 5.02, 6.03, 7.045};//float
*/
import "C"
import "fmt"

func main() {
    goIArray := C.cIArray[:]
    fmt.Println(goIArray)
    goFArray := C.cFArray[:]
    fmt.Println(goFArray)
}

//[]byte 转换为 *char
c_char := (*C.char)(unsafe.Pointer(&bt[0]))