diff --git a/src/daemon.c b/src/daemon.c
index 746fde2..9ec3ea5 100644
--- a/src/daemon.c
+++ b/src/daemon.c
@@ -324,6 +324,7 @@ int main(int argc, char *argv[]) {
         exit(EXIT_FAILURE);
       }
       fprintf(pidfile, "%d\n", getpid());
+      fflush(pidfile);
     } else {
       f2b_log_msg(log_warn, "can't open pidfile: %s", strerror(errno));
     }