diff --git a/vlib/builtin/builtin_windows.c.v b/vlib/builtin/builtin_windows.c.v
index 239d87b80b..160a3fe9bb 100644
--- a/vlib/builtin/builtin_windows.c.v
+++ b/vlib/builtin/builtin_windows.c.v
@@ -70,7 +70,7 @@ fn restore_codepage() {
 
 fn builtin_init() {
 	g_original_codepage = C.GetConsoleOutputCP()
-	C.SetConsoleOutputCP(C.CP_UTF8)	
+	C.SetConsoleOutputCP(C.CP_UTF8)
 	C.atexit(restore_codepage)
 	if is_atty(1) > 0 {
 		C.SetConsoleMode(C.GetStdHandle(C.STD_OUTPUT_HANDLE), C.ENABLE_PROCESSED_OUTPUT | 0x0004) // enable_virtual_terminal_processing
@@ -201,9 +201,9 @@ pub:
 
 type VectoredExceptionHandler fn(&ExceptionPointers)u32
 
-fn C.AddVectoredExceptionHandler(u32, VectoredExceptionHandler)
+fn C.AddVectoredExceptionHandler(u32, C.PVECTORED_EXCEPTION_HANDLER)
 fn add_vectored_exception_handler(handler VectoredExceptionHandler) {
-	C.AddVectoredExceptionHandler(1, handler)
+	C.AddVectoredExceptionHandler(1, C.PVECTORED_EXCEPTION_HANDLER(handler))
 }
 
 [windows_stdcall]
diff --git a/vlib/builtin/cfns.c.v b/vlib/builtin/cfns.c.v
index 3fc4e35dbf..214189a48a 100644
--- a/vlib/builtin/cfns.c.v
+++ b/vlib/builtin/cfns.c.v
@@ -221,7 +221,7 @@ fn C.SendMessageTimeoutW(hWnd voidptr, Msg u32, wParam &u16, lParam &u32, fuFlag
 fn C.CreateProcessW(lpApplicationName &u16, lpCommandLine &u16, lpProcessAttributes voidptr, lpThreadAttributes voidptr, bInheritHandles bool, dwCreationFlags u32, lpEnvironment voidptr, lpCurrentDirectory &u16, lpStartupInfo voidptr, lpProcessInformation voidptr) bool
 
 
-fn C.ReadFile(hFile voidptr, lpBuffer voidptr, nNumberOfBytesToRead u32, lpNumberOfBytesRead voidptr, lpOverlapped voidptr) bool
+fn C.ReadFile(hFile voidptr, lpBuffer voidptr, nNumberOfBytesToRead u32, lpNumberOfBytesRead C.LPDWORD, lpOverlapped voidptr) bool
 
 
 fn C.GetFileAttributesW(lpFileName byteptr) u32
diff --git a/vlib/os/os.v b/vlib/os/os.v
index c689e4f957..f3115e005e 100644
--- a/vlib/os/os.v
+++ b/vlib/os/os.v
@@ -691,13 +691,13 @@ pub fn get_raw_line() string {
 			h_input := C.GetStdHandle(std_input_handle)
 			mut bytes_read := 0
 			if is_atty(0) > 0 {
-				C.ReadConsole(h_input, buf, max_line_chars * 2, &bytes_read, 0)
+				C.ReadConsole(h_input, buf, max_line_chars * 2, C.LPDWORD(&bytes_read), 0)
 				return string_from_wide2(&u16(buf), bytes_read)
 			}
 			mut offset := 0
 			for {
 				pos := buf + offset
-				res := C.ReadFile(h_input, pos, 1, &bytes_read, 0)
+				res := C.ReadFile(h_input, pos, 1, C.LPDWORD(&bytes_read), 0)
 				if !res || bytes_read == 0 {
 						break
 				}
@@ -734,7 +734,7 @@ pub fn get_raw_stdin() []byte {
 			mut offset := 0
 			for {
 				pos := buf + offset
-				res := C.ReadFile(h_input, pos, block_bytes, &bytes_read, 0)
+				res := C.ReadFile(h_input, pos, block_bytes, C.LPDWORD(&bytes_read), 0)
 				offset += bytes_read
 
 				if !res {
diff --git a/vlib/os/os_windows.c.v b/vlib/os/os_windows.c.v
index 1f0adf07d4..1ede7381a8 100644
--- a/vlib/os/os_windows.c.v
+++ b/vlib/os/os_windows.c.v
@@ -345,7 +345,7 @@ pub type VectoredExceptionHandler fn(&ExceptionPointers)u32
 // fn C.AddVectoredExceptionHandler(u32, VectoredExceptionHandler)
 
 pub fn add_vectored_exception_handler(first bool, handler VectoredExceptionHandler) {
-	C.AddVectoredExceptionHandler(u32(first), handler)
+	C.AddVectoredExceptionHandler(u32(first), C.PVECTORED_EXCEPTION_HANDLER(handler))
 }
 
 // this is defined in builtin_windows.c.v in builtin