--- /dev/null
+from typing import Callable, Iterable
+
+_Reader = Callable[[int], bytes]
+
+STDIN_FILENO: int
+STDOUT_FILENO: int
+STDERR_FILENO: int
+
+CHILD: int
+
+def openpty() -> tuple[int, int]: ...
+def master_open() -> tuple[int, str]: ...
+def slave_open(tty_name: str) -> int: ...
+def fork() -> tuple[int, int]: ...
+def spawn(argv: str | Iterable[str], master_read: _Reader = ..., stdin_read: _Reader = ...) -> int: ...