From 280e2a94e50d023f0e34525b8b4e73ae7d542f3e Mon Sep 17 00:00:00 2001
From: Janusz Marcinkiewicz <virrages@gmail.com>
Date: Wed, 5 Apr 2017 19:01:55 +0200
Subject: [PATCH] Worker init clarification; Inform on error thread
 notification failure

---
 torch/lib/THD/master_worker/common/CommandChannel.cpp | 5 ++++-
 torch/lib/THD/master_worker/master/Master.cpp         | 5 +++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/torch/lib/THD/master_worker/common/CommandChannel.cpp b/torch/lib/THD/master_worker/common/CommandChannel.cpp
index 7dff7de98c330e..4b4c4db55f019c 100644
--- a/torch/lib/THD/master_worker/common/CommandChannel.cpp
+++ b/torch/lib/THD/master_worker/common/CommandChannel.cpp
@@ -11,6 +11,7 @@
 #include <string>
 #include <stdexcept>
 #include <utility>
+#include <iostream>
 
 namespace thd {
 namespace {
@@ -55,7 +56,9 @@ MasterCommandChannel::MasterCommandChannel()
 
 MasterCommandChannel::~MasterCommandChannel() {
   if (_error_thread.joinable()) {
-    ::write(_error_pipe, "exit", 4);
+    if (::write(_error_pipe, "exit", 4) != 4) {
+      std::cerr << "Failed to notify error thread" << std::endl;
+    }
     _error_thread.join();
 
     ::close(_error_pipe);
diff --git a/torch/lib/THD/master_worker/master/Master.cpp b/torch/lib/THD/master_worker/master/Master.cpp
index 812fe64d9074d5..63db2c044654f5 100644
--- a/torch/lib/THD/master_worker/master/Master.cpp
+++ b/torch/lib/THD/master_worker/master/Master.cpp
@@ -20,8 +20,9 @@ bool THDMasterWorkerInit(THDChannelType channel_type) {
 
   if (dataChannel->getRank() > 0) {
     /*
-     * Worker initialization. If initialization succeeds it goes into
-     * infinite loop in which waits for commands from master.
+     * Worker initialization. It goes into infinite loop in which waits
+     * for commands from master. Returning from `THDWorkerMain` indicates
+     * a failure so it will `return false`.
      */
     THDWorkerMain();
     return false;