diff --git a/src/sysinput.c b/src/sysinput.c
index c45d6f7..503c2f3 100644
--- a/src/sysinput.c
+++ b/src/sysinput.c
@@ -5,7 +5,7 @@
 #include "msg_queue.h"
 #include "gpio.h"
 
-PMSG_QUEUE Sys_Queue = NULL;
+volatile PMSG_QUEUE Sys_Queue = NULL;
 
 static pthread_t ithread;
 static volatile sig_atomic_t running = 1;
diff --git a/src/sysinput.h b/src/sysinput.h
index 29b5a18..bc08960 100644
--- a/src/sysinput.h
+++ b/src/sysinput.h
@@ -3,7 +3,7 @@
 
 #include "msg_queue.h"
 
-extern PMSG_QUEUE Sys_Queue;
+extern volatile PMSG_QUEUE Sys_Queue;
 
 extern int SysEnableInput(void);
 extern void SysDisableInput(void);