diff --git a/usr.bin/bintrans/uudecode.c b/usr.bin/bintrans/uudecode.c
--- a/usr.bin/bintrans/uudecode.c
+++ b/usr.bin/bintrans/uudecode.c
@@ -406,6 +406,8 @@
 				}
 			}
 	}
+	if (fflush(outfp) != 0)
+		err(1, "write error");
 	switch (get_line(buf, sizeof(buf))) {
 	case 0:
 		return (0);
@@ -459,6 +461,8 @@
 			break;
 		fwrite(outbuf, 1, n, outfp);
 	}
+	if (fflush(outfp) != 0)
+		err(1, "write error");
 	return (checkend(inbuf, "====", "error decoding base64 input stream"));
 }
 
diff --git a/usr.bin/bintrans/uuencode.c b/usr.bin/bintrans/uuencode.c
--- a/usr.bin/bintrans/uuencode.c
+++ b/usr.bin/bintrans/uuencode.c
@@ -74,7 +74,7 @@
 	if (w != NULL)
 		columns = arg_to_col(w);
 	base64_encode();
-	if (ferror(output))
+	if (fflush(output) != 0)
 		errx(1, "write error");
 	exit(0);
 }
@@ -144,7 +144,7 @@
 		base64_encode();
 	else
 		encode();
-	if (ferror(output))
+	if (fflush(output) != 0)
 		errx(1, "write error");
 	exit(0);
 }