odbtest/test/shm/shm_w.go

package main
 
import(
	"fmt"
	"time"
	//"strings"
	"unsafe"
	"github.com/hidez8891/shm"
)

const SHM_NAME = "my_shm"
const SHM_SIZE = 4 * 1000 * 1000

type MyData struct {
    ss 		string
	ii		int
}

func main() {

	w, err := shm.Create(SHM_NAME, SHM_SIZE)
	if err != nil {
		fmt.Printf("fail: create shared memroy %v", err)
	}
	
	const sz = int( unsafe.Sizeof( MyData{} ) )
	
	data := MyData{ss:"hello world", ii:100}
	var asByteSlice []byte = (*(*[sz]byte)(unsafe.Pointer(&data)))[:]
	
	n, err := w.WriteAt(asByteSlice, 0)
	if err != nil {
		fmt.Printf("fail: write shared memroy %v", err)
	}
	
	fmt.Printf("wn==>%d", n)
	
	/*r, err := shm.Open("aaa", 64)
	if err != nil {
		fmt.Printf("fail: open shared memroy %v", err)
	}
	
	buf := make([]byte, len(data))
	n, err = r.ReadAt(buf, 0)
	if err != nil {
		fmt.Printf("fail: read shared memroy %v", err)
	}
	fmt.Println("rn==>%d", n)
	
	r.Close()
	*/
	time.Sleep(time.Duration(30)*time.Second)
	
	//w.Close()
	
}