From cc48937a4fa1ee33af896dbe16c876e09958a52d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Blanchon?=
 <bblanchon@users.noreply.github.com>
Date: Tue, 23 Aug 2016 15:54:01 +0200
Subject: [PATCH] Updated Compatibility issues (markdown)

---
 Compatibility-issues.md | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/Compatibility-issues.md b/Compatibility-issues.md
index a486983..1561d9f 100644
--- a/Compatibility-issues.md
+++ b/Compatibility-issues.md
@@ -152,4 +152,17 @@ They are located here on Windows:
 
 ```
 %LOCALAPPDATA%\Arduino15\packages\arduino\hardware\samd\1.6.6\cores\arduino\USB
-```
\ No newline at end of file
+```
+
+## GCC warning: ignoring packed attribute because of unpacked non-POD field
+
+If you pass the flag `--fpack-struct` to the compiler, it will generate the following warning:
+
+```
+warning: ignoring packed attribute because of unpacked non-POD field
+```
+
+No solution has been found so far: you need to remove that flag if you want to get rid of that warning.
+
+See issue [#255](https://github.com/bblanchon/ArduinoJson/issues/255)
+