diff --git a/inc/lektor/internal/os.h b/inc/lektor/internal/os.h
index d85395c61a96d3226c220637b8925220aa62ccb1..614ac88ce8f82a3936857f0abbacb7ab79d4bd0e 100644
--- a/inc/lektor/internal/os.h
+++ b/inc/lektor/internal/os.h
@@ -221,7 +221,7 @@ is_error_broken_pipe(int UNUSED error)
 
 #if defined(LKT_OS_WIN) && (LKT_OS_WIN == 1)
 PRIVATE_FUNCTION int
-poll(fd_set *fds, nfds_t nfds, int timeout)
+poll(LPWSAPOLLFD *fds, ULONG nfds, INT timeout)
 {
     return WSAPoll(fds, nfds, timeout);
 }