diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go
index 6b40a255d5..beaeda97fa 100644
--- a/src/cmd/cgo/out.go
+++ b/src/cmd/cgo/out.go
@@ -236,6 +236,7 @@ func (p *Package) writeDefs() {
 		if err != nil {
 			fatalf("%s", err)
 		}
+		defer fgcch.Close()
 		_, err = io.Copy(fexp, fgcch)
 		if err != nil {
 			fatalf("%s", err)