From f6de8014b816767e5fdf56aa7920f5564f26df0c Mon Sep 17 00:00:00 2001
From: Tom Early <n7tae@tearly.net>
Date: Sat, 7 Apr 2018 12:03:53 -0700
Subject: [PATCH] added FD_ISSET() to UDPSocket::read()

---
 UDPSocket.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/UDPSocket.cpp b/UDPSocket.cpp
index 7295ee9..d7c45f3 100644
--- a/UDPSocket.cpp
+++ b/UDPSocket.cpp
@@ -113,7 +113,7 @@ int CUDPSocket::read(unsigned char* buffer, unsigned int length, in_addr& addres
 	FD_ZERO(&readFds);
 	FD_SET(m_fd, &readFds);
 
-	// Return immediately
+	// Return immediately if there is nothing for this socket
 	timeval tv;
 	tv.tv_sec  = 0L;
 	tv.tv_usec = 0L;
@@ -127,6 +127,9 @@ int CUDPSocket::read(unsigned char* buffer, unsigned int length, in_addr& addres
 	if (ret == 0)
 		return 0;
 
+	if (! FD_ISSET(m_fd, &readFds))
+		return 0;	// nothing for this socket;
+
 	sockaddr_in addr;
 	socklen_t size = sizeof(sockaddr_in);