From fe791d78866941da4996e14b43706fead913b447 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Fri, 20 Jan 2017 18:44:36 -0700
Subject: [PATCH] Use libc errno

---
 src/libstd/sys/redox/os.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/libstd/sys/redox/os.rs b/src/libstd/sys/redox/os.rs
index 135e972bca4..9d459581dd4 100644
--- a/src/libstd/sys/redox/os.rs
+++ b/src/libstd/sys/redox/os.rs
@@ -33,9 +33,16 @@ use vec;
 const TMPBUF_SZ: usize = 128;
 static ENV_LOCK: Mutex = Mutex::new();
 
+extern {
+    #[link_name = "__errno_location"]
+    fn errno_location() -> *mut i32;
+}
+
 /// Returns the platform-specific value of errno
 pub fn errno() -> i32 {
-    0
+    unsafe {
+        (*errno_location())
+    }
 }
 
 /// Gets a detailed string description for the given error number.