diff --git a/libutil/fshut.c b/libutil/fshut.c
index f243a82..4de6596 100644
--- a/libutil/fshut.c
+++ b/libutil/fshut.c
@@ -7,10 +7,12 @@ int fshut(FILE *fp, const char *fname)
 {
 	int ret = 0;
 
-	if (fflush(fp) && !ret) {
-		weprintf("fflush %s:", fname);
-		ret = 1;
-	}
+	/* fflush() is undefined for input streams by ISO C,
+	 * but not POSIX 2008 if you ignore ISO C overrides.
+	 * Leave it unchecked an rely on the following
+	 * functions to detect errors.
+	 */
+	fflush(fp);
 
 	if (ferror(fp) && !ret) {
 		weprintf("ferror %s:", fname);