diff --git a/ClanLib/Sources/Core/IOData/Generic/inputsource_file.cpp b/ClanLib/Sources/Core/IOData/Generic/inputsource_file.cpp

index d0413e5..7b3da2a 100644

--- a/ClanLib/Sources/Core/IOData/Generic/inputsource_file.cpp

+++ b/ClanLib/Sources/Core/IOData/Generic/inputsource_file.cpp

@@ -27,6 +27,8 @@

 **    (if your name is missing here, please add it)

 */

+#include <unistd.h>

+

 #include "Core/precomp.h"

 #ifdef WIN32