From 47f7e3590f7e7cb1bec9ba9873ba1a0ee76cf0cc Mon Sep 17 00:00:00 2001
From: Wesley Moxam <wes@4ormat.com>
Date: Sat, 18 Nov 2017 12:53:27 -0500
Subject: [PATCH] Fixes setting IO blocking on OpenBSD (#5283)

---
 src/io/file_descriptor.cr | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/io/file_descriptor.cr b/src/io/file_descriptor.cr
index 5ffcf75e3cd8..4250ccc69ed5 100644
--- a/src/io/file_descriptor.cr
+++ b/src/io/file_descriptor.cr
@@ -22,13 +22,14 @@ class IO::FileDescriptor < IO
   end
 
   def blocking=(value)
-    flags = fcntl(LibC::F_GETFL)
+    current_flags = fcntl(LibC::F_GETFL)
+    new_flags = current_flags
     if value
-      flags &= ~LibC::O_NONBLOCK
+      new_flags &= ~LibC::O_NONBLOCK
     else
-      flags |= LibC::O_NONBLOCK
+      new_flags |= LibC::O_NONBLOCK
     end
-    fcntl(LibC::F_SETFL, flags)
+    fcntl(LibC::F_SETFL, new_flags) unless new_flags == current_flags
   end
 
   def close_on_exec?