diff --git a/IB/PosixSocketClient/EPosixClientSocketPlatform.h b/IB/PosixSocketClient/EPosixClientSocketPlatform.h
index 9fc7197..f1079c4 100644
--- a/IB/PosixSocketClient/EPosixClientSocketPlatform.h
+++ b/IB/PosixSocketClient/EPosixClientSocketPlatform.h
@@ -26,6 +26,7 @@
 	#include <arpa/inet.h>
 	#include <errno.h>
 	#include <sys/select.h>
+	#include <unistd.h>
 
 	// helpers
 	inline bool SocketsInit() { return true; };
