diff --git a/CMakeLists.txt b/CMakeLists.txt
index f69560d..313dcbe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,7 +8,7 @@ if(WIN32)
 endif()
 
 if(MSVC)
-	add_compile_options(/Wall /wd4201 /wd4206 /wd4242 /wd4244 /wd4255 /wd4267 /wd4310 /wd4706 /wd4710 /wd4711 /wd4820 /wd4996)
+	add_compile_options(/Wall /wd4201 /wd4206 /wd4242 /wd4244 /wd4267 /wd4310 /wd4706 /wd4710 /wd4711 /wd4820 /wd4996)
 else()
 	add_compile_options(-Wall)
 endif()
diff --git a/include/epoll.h b/include/epoll.h
index a49997e..d997c2b 100644
--- a/include/epoll.h
+++ b/include/epoll.h
@@ -59,7 +59,7 @@ struct epoll_event {
 extern "C" {
 #endif
 
-EPOLL_EXTERN epoll_t epoll_create();
+EPOLL_EXTERN epoll_t epoll_create(void);
 
 EPOLL_EXTERN int epoll_close(epoll_t epoll_hnd);
 
diff --git a/src/epoll.c b/src/epoll.c
index 566d2af..6ac51bb 100644
--- a/src/epoll.c
+++ b/src/epoll.c
@@ -35,7 +35,7 @@ typedef struct epoll_port_data epoll_port_data_t;
 typedef struct epoll_io_req epoll_io_req_t;
 typedef struct epoll_sock_data epoll_sock_data_t;
 
-static int epoll__initialize();
+static int epoll__initialize(void);
 static SOCKET epoll__get_peer_socket(epoll_port_data_t* port_data,
                                      WSAPROTOCOL_INFOW* protocol_info);
 static SOCKET epoll__create_peer_socket(HANDLE iocp,
@@ -85,7 +85,7 @@ RB_GENERATE_STATIC(epoll_sock_data_tree,
                    tree_entry,
                    epoll__compare_sock_data)
 
-epoll_t epoll_create() {
+epoll_t epoll_create(void) {
   epoll_port_data_t* port_data;
   HANDLE iocp;
 
@@ -549,7 +549,7 @@ int epoll_close(epoll_t port_handle) {
   return_success(0);
 }
 
-int epoll__initialize() {
+int epoll__initialize(void) {
   int r;
   WSADATA wsa_data;
 
diff --git a/src/nt.c b/src/nt.c
index 4c8293b..d3a1515 100644
--- a/src/nt.c
+++ b/src/nt.c
@@ -8,7 +8,7 @@
 NTDLL_IMPORT_LIST(X)
 #undef X
 
-int nt_initialize() {
+int nt_initialize(void) {
   HMODULE ntdll;
 
   ntdll = LoadLibraryW(L"ntdll.dll");
diff --git a/src/nt.h b/src/nt.h
index a033888..9e3a57c 100644
--- a/src/nt.h
+++ b/src/nt.h
@@ -4,7 +4,7 @@
 #include "ntstatus.h"
 #include "win.h"
 
-int nt_initialize();
+int nt_initialize(void);
 
 typedef struct _IO_STATUS_BLOCK {
   union {