Golang函数的系统调用和文件系统操作的应用技巧

data := []byte("hello, world!") 
file, err := syscall.Open("./test.txt", syscall.O_CREAT|syscall.O_TRUNC|syscall.O_RDWR, 0666) 
if err != nil {
    panic(err)
}
defer syscall.Close(file) 

_, _, err = syscall.Syscall(syscall.SYS_WRITE, uintptr(file), uintptr(unsafe.Pointer(&data[0])), uintptr(len(data))) 
if err != 0 {
    panic(err)
}

h, _, _ := syscall.Syscall(
    procCreateFileW.Addr(),
    6,
    uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(path))),
    uintptr(desiredAccess),
    uintptr(shareMode),
    uintptr(unsafe.Pointer(lpSecurityAttributes)),
    uintptr(creationDisposition),
    uintptr(flagsAndAttributes),
)

if h == uintptr(syscall.InvalidHandle) {
    return nil, os.NewSyscallError(fmt.Sprintf("invalid handle: %X", h), err)
}
defer syscall.CloseHandle(syscall.Handle(h))

data, err := ioutil.ReadFile("./test.txt")
if err != nil {
    panic(err)
}

fmt.Print(string(data))

data := []byte("hello, world!")
err := ioutil.WriteFile("./test.txt", data, 0666)
if err != nil {
    panic(err)
}

err := os.Mkdir("./test", 0755)
if err != nil {
    panic(err)
}

err := os.Remove("./test.txt")
if err != nil {
    panic(err)
}

err := os.Rename("./test.txt", "./test_new.txt")
if err != nil {
    panic(err)
}

info, err := os.Stat("./test_new.txt")
if err != nil {
    panic(err)
}

fmt.Println(info.Name(), info.Size())