c与go 类型转换
最后更新于：2022-04-02 02:41:57
[TOC]
### 概述
```
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
```
## demo
```
package main
/*
#include
#include
char ch = 'M';
unsigned char uch = 253;
short st = 233;
int i = 257;
long lt = 11112222;
float f = 3.14;
double db = 3.15;
void * p;
char *str = "const string";
char str1[64] = "char array";
void printI(void *i)
{
printf("print i = %d\n", (*(int *)i));
}
struct ImgInfo {
char *imgPath;
int format;
unsigned int width;
unsigned int height;
};
void printStruct(struct ImgInfo *imgInfo)
{
if(!imgInfo) {
fprintf(stderr, "imgInfo is null\n");
return ;
}
fprintf(stdout, "imgPath = %s\n", imgInfo->imgPath);
fprintf(stdout, "format = %d\n", imgInfo->format);
fprintf(stdout, "width = %d\n", imgInfo->width);
}
*/
import "C"
import (
"fmt"
"reflect"
"unsafe"
)
func main() {
fmt.Println("----------------Go to C---------------")
fmt.Println(C.char('Y'))
fmt.Printf("%c\n", C.char('Y'))
fmt.Println(C.uchar('C'))
fmt.Println(C.short(254))
fmt.Println(C.long(11112222))
var goi int = 2
// unsafe.Pointer --> void *
cpi := unsafe.Pointer(&goi)
C.printI(cpi)
fmt.Println("----------------C to Go---------------")
fmt.Println(C.ch)
fmt.Println(C.uch)
fmt.Println(C.st)
fmt.Println(C.i)
fmt.Println(C.lt)
f := float32(C.f)
fmt.Println(reflect.TypeOf(f))
fmt.Println(C.f)
db := float64(C.db)
fmt.Println(reflect.TypeOf(db))
fmt.Println(C.db)
// 区别常量字符串和char数组，转换成Go类型不一样
str := C.GoString(C.str)
fmt.Println(str)
fmt.Println(reflect.TypeOf(C.str1))
var charray []byte
for i := range C.str1 {
if C.str1[i] != 0 {
charray = append(charray, byte(C.str1[i]))
}
}
fmt.Println(charray)
fmt.Println(string(charray))
for i := 0; i < 10; i++ {
imgInfo := C.struct_ImgInfo{imgPath: C.CString("../images/xx.jpg"), format: 0, width: 500, height: 400}
defer C.free(unsafe.Pointer(imgInfo.imgPath))
C.printStruct(&imgInfo)
}
fmt.Println("----------------C Print----------------")
}
```
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