lockFileFailImmediately = 1

	// see https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx
	errLockViolation syscall.Errno = 0x21
)

// lockedOpenFile is an internal function.
func lockedOpenFile(path string, flag int, perm os.FileMode, lockType uint32) (*LockedFile, error) {
	f, err := Open(path, flag, perm)
	if err != nil {
		return nil, err
	}

pkg syscall (freebsd-arm64), func Dup2(int, int) error
pkg syscall (freebsd-arm64), func Fchdir(int) error
pkg syscall (freebsd-arm64), func Fchflags(int, int) error
pkg syscall (freebsd-arm64), func Fchmod(int, uint32) error
pkg syscall (freebsd-arm64), func Fchown(int, int, int) error
pkg syscall (freebsd-arm64), func FcntlFlock(uintptr, int, *Flock_t) error
pkg syscall (freebsd-arm64), func Flock(int, int) error

pkg syscall (freebsd-riscv64), func Setegid(int) error #53466
pkg syscall (freebsd-riscv64), func Seteuid(int) error #53466
pkg syscall (freebsd-riscv64), func Setgid(int) error #53466
pkg syscall (freebsd-riscv64), func Setgroups([]int) error #53466
pkg syscall (freebsd-riscv64), func Setlogin(string) error #53466
pkg syscall (freebsd-riscv64), func Setpgid(int, int) error #53466

	}
	if context == ctxAssign2 {
		context = ctxExpr
	}
	if context == ctxEmbedType {
		error_(sel.Pos(), "cannot embed C type")
	}
	goname := sel.Sel.Name
	if goname == "errno" {
		error_(sel.Pos(), "cannot refer to errno directly; see documentation")
		return
	}
	if goname == "_CMalloc" {
		error_(sel.Pos(), "cannot refer to C._CMalloc; use C.malloc")
		return
	}
	if goname == "malloc" {

				if err.Error() != testCase.expectedErr.Error() {
					if runtime.GOOS != globalWindowsOSName {
						t.Errorf("Case: %d %#v, expected: %s, got: %s", i+1, testCase, testCase.expectedErr, err)
					} else {
						var resultErrno, expectErrno uintptr
						if pathErr, ok := err.(*os.PathError); ok {
							if errno, pok := pathErr.Err.(syscall.Errno); pok {
								resultErrno = uintptr(errno)

<img src="/img/python-types/image06.png">

Notice that this means "`one_person` is an **instance** of the class `Person`".

It doesn't mean "`one_person` is the **class** called `Person`".

## Pydantic models

<a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> is a Python library to perform data validation.

You declare the "shape" of the data as classes with attributes.

			// with EAGAIN.
			if pe, ok := err.(*os.PathError); ok {
				err = pe.Err
			}
			if se, ok := err.(syscall.Errno); ok && (se == syscall.EAGAIN || se == syscall.EMFILE) {
				time.Sleep(time.Millisecond)
				continue
			}

			t.Error(err)
			return
		}
		cmds = append(cmds, cmd)
	}

	failures := 0
	for _, cmd := range cmds {
		err := cmd.Wait()

      contain a complex error message if error_msg does not provide enough
      information. In that case, set suppress_default_error to True.
    error_msg: (String) String with one and only one '%s'. Formatted with each
      invalid response upon check_success(input) failure.
    suppress_default_error: (Bool) Suppress the above error message in favor of
      one from the check_success function.

An error on not-int-const:1 indicates that foo is not an integer constant.
An error on not-num-const:1 indicates that foo is not a number constant.
An error on not-str-lit:1 indicates that foo is not a string literal.
An error on not-signed-int-const:1 indicates that foo is not a signed integer constant.

The line number specifies the name involved. In the example, 1 is foo.

Next, cgo must learn the details of each type, variable, function, or

<img src="/img/python-types/image06.png">

Lưu ý rằng, điều này có nghĩa rằng "`one_person`" là một **thực thể** của lớp `Person`.

Nó không có nghĩa "`one_person`" là một **lớp** gọi là `Person`.

## Pydantic models

<a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> là một thư viện Python để validate dữ liệu hiệu năng cao.