diff --git a/stdlib/asyncio/unix_events.pyi b/stdlib/asyncio/unix_events.pyi
index 2fbc0a4e6..e9274b853 100644
--- a/stdlib/asyncio/unix_events.pyi
+++ b/stdlib/asyncio/unix_events.pyi
@@ -17,7 +17,9 @@ if sys.version_info >= (3, 12):
     @deprecated("Deprecated as of Python 3.12; will be removed in Python 3.14")
     class AbstractChildWatcher:
         @abstractmethod
-        def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+        def add_child_handler(
+            self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+        ) -> None: ...
         @abstractmethod
         def remove_child_handler(self, pid: int) -> bool: ...
         @abstractmethod
@@ -36,7 +38,9 @@ if sys.version_info >= (3, 12):
 else:
     class AbstractChildWatcher:
         @abstractmethod
-        def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+        def add_child_handler(
+            self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+        ) -> None: ...
         @abstractmethod
         def remove_child_handler(self, pid: int) -> bool: ...
         @abstractmethod
@@ -87,27 +91,35 @@ if sys.platform != "win32":
         class SafeChildWatcher(BaseChildWatcher):
             def __enter__(self) -> Self: ...
             def __exit__(self, a: type[BaseException] | None, b: BaseException | None, c: types.TracebackType | None) -> None: ...
-            def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+            def add_child_handler(
+                self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+            ) -> None: ...
             def remove_child_handler(self, pid: int) -> bool: ...
 
         @deprecated("Deprecated as of Python 3.12; will be removed in Python 3.14")
         class FastChildWatcher(BaseChildWatcher):
             def __enter__(self) -> Self: ...
             def __exit__(self, a: type[BaseException] | None, b: BaseException | None, c: types.TracebackType | None) -> None: ...
-            def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+            def add_child_handler(
+                self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+            ) -> None: ...
             def remove_child_handler(self, pid: int) -> bool: ...
 
     else:
         class SafeChildWatcher(BaseChildWatcher):
             def __enter__(self) -> Self: ...
             def __exit__(self, a: type[BaseException] | None, b: BaseException | None, c: types.TracebackType | None) -> None: ...
-            def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+            def add_child_handler(
+                self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+            ) -> None: ...
             def remove_child_handler(self, pid: int) -> bool: ...
 
         class FastChildWatcher(BaseChildWatcher):
             def __enter__(self) -> Self: ...
             def __exit__(self, a: type[BaseException] | None, b: BaseException | None, c: types.TracebackType | None) -> None: ...
-            def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+            def add_child_handler(
+                self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+            ) -> None: ...
             def remove_child_handler(self, pid: int) -> bool: ...
 
     class _UnixSelectorEventLoop(BaseSelectorEventLoop): ...
@@ -135,7 +147,9 @@ if sys.platform != "win32":
             def __exit__(
                 self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: types.TracebackType | None
             ) -> None: ...
-            def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+            def add_child_handler(
+                self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+            ) -> None: ...
             def remove_child_handler(self, pid: int) -> bool: ...
             def attach_loop(self, loop: AbstractEventLoop | None) -> None: ...
 
@@ -147,7 +161,9 @@ if sys.platform != "win32":
             def __exit__(
                 self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: types.TracebackType | None
             ) -> None: ...
-            def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+            def add_child_handler(
+                self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+            ) -> None: ...
             def remove_child_handler(self, pid: int) -> bool: ...
             def attach_loop(self, loop: AbstractEventLoop | None) -> None: ...
 
@@ -159,7 +175,9 @@ if sys.platform != "win32":
             self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: types.TracebackType | None
         ) -> None: ...
         def __del__(self) -> None: ...
-        def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+        def add_child_handler(
+            self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+        ) -> None: ...
         def remove_child_handler(self, pid: int) -> bool: ...
         def attach_loop(self, loop: AbstractEventLoop | None) -> None: ...
 
@@ -172,5 +190,7 @@ if sys.platform != "win32":
             def is_active(self) -> bool: ...
             def close(self) -> None: ...
             def attach_loop(self, loop: AbstractEventLoop | None) -> None: ...
-            def add_child_handler(self, pid: int, callback: Callable[[Unpack[_Ts]], object], *args: Unpack[_Ts]) -> None: ...
+            def add_child_handler(
+                self, pid: int, callback: Callable[[int, int, Unpack[_Ts]], object], *args: Unpack[_Ts]
+            ) -> None: ...
             def remove_child_handler(self, pid: int) -> bool: ...