diff --git a/src/save.c b/src/save.c
index 62d2325ef..a5519b807 100644
--- a/src/save.c
+++ b/src/save.c
@@ -723,11 +723,13 @@ bufon(fd)
     int fd;
 {
 #ifdef UNIX
-    if(bw_fd >= 0)
-	panic("double buffering unexpected");
-    bw_fd = fd;
-    if((bw_FILE = fdopen(fd, "w")) == 0)
-	panic("buffering of file %d failed", fd);
+    if(bw_fd != fd) {
+	if(bw_fd >= 0)
+	    panic("double buffering unexpected");
+	bw_fd = fd;
+	if((bw_FILE = fdopen(fd, "w")) == 0)
+	    panic("buffering of file %d failed", fd);
+    }
 #endif
     buffering = TRUE;
 }