From 9f16513ebe94fbe6f5a32784b06360ff4b5237ae Mon Sep 17 00:00:00 2001
From: Simon Giesecke <simon.giesecke@gmail.com>
Date: Tue, 10 Dec 2019 16:19:25 +0100
Subject: [PATCH] Problem: loop sending signaler event is obscure

Solution: add comments and remove continue/break
---
 src/signaler.cpp | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/src/signaler.cpp b/src/signaler.cpp
index b4300d6c..e55360dc 100644
--- a/src/signaler.cpp
+++ b/src/signaler.cpp
@@ -183,16 +183,15 @@ void zmq::signaler_t::send ()
     ssize_t sz = write (_w, &inc, sizeof (inc));
     errno_assert (sz == sizeof (inc));
 #elif defined ZMQ_HAVE_WINDOWS
-    unsigned char dummy = 0;
-    while (true) {
-        int nbytes =
-          ::send (_w, reinterpret_cast<char *> (&dummy), sizeof (dummy), 0);
+    const char dummy = 0;
+    int nbytes;
+    do {
+        nbytes = ::send (_w, &dummy, sizeof (dummy), 0);
         wsa_assert (nbytes != SOCKET_ERROR);
-        if (unlikely (nbytes == SOCKET_ERROR))
-            continue;
-        zmq_assert (nbytes == sizeof (dummy));
-        break;
-    }
+        // wsa_assert does not abort on WSAEWOULDBLOCK. If we get this, we retry.
+    } while (nbytes == SOCKET_ERROR);
+    // Given the small size of dummy (should be 1) expect that send was able to send everything.
+    zmq_assert (nbytes == sizeof (dummy));
 #elif defined ZMQ_HAVE_VXWORKS
     unsigned char dummy = 0;
     while (true) {