diff --git a/src/epoll.c b/src/epoll.c
index 0cb3618..6c592a4 100644
--- a/src/epoll.c
+++ b/src/epoll.c
@@ -8,19 +8,13 @@
 #include "error.h"
 #include "nt.h"
 #include "tree.h"
+#include "util.h"
 #include "win.h"
 
 #ifndef SIO_BASE_HANDLE
 #define SIO_BASE_HANDLE 0x48000022
 #endif
 
-#ifndef _SSIZE_T_DEFINED
-#define SSIZE_T_DEFINED
-typedef intptr_t ssize_t;
-#endif
-
-#define ARRAY_COUNT(a) (sizeof(a) / (sizeof((a)[0])))
-
 #define EPOLL__EVENT_MASK 0xffff
 
 #define EPOLL__SOCK_LISTED 0x1
diff --git a/src/util.h b/src/util.h
new file mode 100644
index 0000000..982d86d
--- /dev/null
+++ b/src/util.h
@@ -0,0 +1,11 @@
+#ifndef EPOLL_UTIL_H_
+#define EPOLL_UTIL_H_
+
+#ifndef _SSIZE_T_DEFINED
+#define SSIZE_T_DEFINED
+typedef intptr_t ssize_t;
+#endif
+
+#define ARRAY_COUNT(a) (sizeof(a) / (sizeof((a)[0])))
+
+#endif /* EPOLL_UTIL_H_ */