diff --git a/vlib/builtin/builtin_windows.c.v b/vlib/builtin/builtin_windows.c.v
index 16f01c8590..aaa99be6af 100644
--- a/vlib/builtin/builtin_windows.c.v
+++ b/vlib/builtin/builtin_windows.c.v
@@ -286,8 +286,7 @@ pub fn winapi_lasterr_str() string {
 	}
 	mut msgbuf := &u16(0)
 	res := C.FormatMessage(C.FORMAT_MESSAGE_ALLOCATE_BUFFER | C.FORMAT_MESSAGE_FROM_SYSTEM | C.FORMAT_MESSAGE_IGNORE_INSERTS,
-		C.NULL, err_msg_id, C.MAKELANGID(C.LANG_NEUTRAL, C.SUBLANG_DEFAULT), &msgbuf,
-		0, C.NULL)
+		0, err_msg_id, 0, voidptr(&msgbuf), 0, 0)
 	err_msg := if res == 0 {
 		'Win-API error ${err_msg_id}'
 	} else {
diff --git a/vlib/builtin/cfns.c.v b/vlib/builtin/cfns.c.v
index 597d3f8e8f..32f718b253 100644
--- a/vlib/builtin/cfns.c.v
+++ b/vlib/builtin/cfns.c.v
@@ -349,7 +349,7 @@ fn C.FindClose(hFindFile voidptr)
 // macro
 fn C.MAKELANGID(lgid voidptr, srtid voidptr) int
 
-fn C.FormatMessage(dwFlags u32, lpSource voidptr, dwMessageId u32, dwLanguageId u32, lpBuffer voidptr, nSize int, arguments ...voidptr) voidptr
+fn C.FormatMessage(dwFlags u32, lpSource voidptr, dwMessageId u32, dwLanguageId u32, lpBuffer voidptr, nSize u32, arguments ...voidptr) u32
 
 fn C.CloseHandle(voidptr) int
 
diff --git a/vlib/os/os_windows.c.v b/vlib/os/os_windows.c.v
index 984c820f94..d6dba2538c 100644
--- a/vlib/os/os_windows.c.v
+++ b/vlib/os/os_windows.c.v
@@ -262,8 +262,7 @@ fn ptr_win_get_error_msg(code u32) voidptr {
 		return buf
 	}
 	C.FormatMessage(os.format_message_allocate_buffer | os.format_message_from_system | os.format_message_ignore_inserts,
-		0, code, C.MAKELANGID(os.lang_neutral, os.sublang_default), voidptr(&buf), 0,
-		0)
+		0, code, 0, voidptr(&buf), 0, 0)
 	return buf
 }