From bad085c644fe9351af3c306ebc93d14c9a4fdca0 Mon Sep 17 00:00:00 2001
From: alexhqwang <62671723+alexhqwang@users.noreply.github.com>
Date: Thu, 20 Jan 2022 21:13:30 -0800
Subject: [PATCH] Add IsSelectResultValid to LayerImplSelect (#13776)

---
 src/system/SystemLayerImplSelect.cpp | 2 +-
 src/system/SystemLayerImplSelect.h   | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/system/SystemLayerImplSelect.cpp b/src/system/SystemLayerImplSelect.cpp
index 0ac3bd3e7ad7bc..1feaf7d3feb7ad 100644
--- a/src/system/SystemLayerImplSelect.cpp
+++ b/src/system/SystemLayerImplSelect.cpp
@@ -373,7 +373,7 @@ void LayerImplSelect::HandleEvents()
 {
     assertChipStackLockedByCurrentThread();
 
-    if (mSelectResult < 0)
+    if (!IsSelectResultValid())
     {
         ChipLogError(DeviceLayer, "select failed: %s\n", ErrorStr(CHIP_ERROR_POSIX(errno)));
         return;
diff --git a/src/system/SystemLayerImplSelect.h b/src/system/SystemLayerImplSelect.h
index 9211971ea1c28a..d714f7929067a5 100644
--- a/src/system/SystemLayerImplSelect.h
+++ b/src/system/SystemLayerImplSelect.h
@@ -75,6 +75,9 @@ class LayerImplSelect : public LayerSocketsLoop
     void HandleTimerComplete(TimerList::Node * timer);
 #endif // CHIP_SYSTEM_CONFIG_USE_DISPATCH
 
+    // Expose the result of WaitForEvents() for non-blocking socket implementations.
+    bool IsSelectResultValid() const { return mSelectResult >= 0; }
+
 protected:
     static SocketEvents SocketEventsFromFDs(int socket, const fd_set & readfds, const fd_set & writefds, const fd_set & exceptfds);