From fc9283964affdb5c719c9bd86b213d7937a7f37b Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Thu, 30 Jun 2016 20:45:03 +1000
Subject: [PATCH] HAL_SITL: fixed segv on cygwin

---
 libraries/AP_HAL_SITL/UARTDriver.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libraries/AP_HAL_SITL/UARTDriver.cpp b/libraries/AP_HAL_SITL/UARTDriver.cpp
index b468481535..a03d92c7e0 100644
--- a/libraries/AP_HAL_SITL/UARTDriver.cpp
+++ b/libraries/AP_HAL_SITL/UARTDriver.cpp
@@ -367,6 +367,9 @@ void UARTDriver::_check_connection(void)
  */
 bool UARTDriver::_select_check(int fd)
 {
+    if (fd == -1) {
+        return false;
+    }
     fd_set fds;
     struct timeval tv;