diff --git a/vlib/os/os.v b/vlib/os/os.v
index fd2cb52fe1..7dc3b96b9e 100644
--- a/vlib/os/os.v
+++ b/vlib/os/os.v
@@ -239,6 +239,10 @@ pub fn (f File) writeln(s string) {
 	C.fputs('\n', f.cfile)
 }
 
+pub fn (f File) flush() {
+	C.fflush(f.cfile)
+}
+
 pub fn (f File) close() {
 	C.fclose(f.cfile)
 }