--- ray/src/common/readoct.c	2019/05/04 00:32:47	2.31
+++ ray/src/common/readoct.c	2023/06/08 17:39:13	2.33
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: readoct.c,v 2.31 2019/05/04 00:32:47 greg Exp $";
+static const char	RCSid[] = "$Id: readoct.c,v 2.33 2023/06/08 17:39:13 greg Exp $";
 #endif
 /*
  *  readoct.c - routines to read octree information.
@@ -41,6 +41,8 @@ readoct(				/* read in octree file or stream */
 	char  *ofn[]
 )
 {
+	time_t  oct_t = 0;
+	time_t	last_it = 0;
 	char  sbuf[512];
 	int  nf;
 	int  i;
@@ -62,7 +64,11 @@ readoct(				/* read in octree file or stream */
 					inpspec);
 			error(SYSTEM, errmsg);
 		}
+		oct_t = fddate(fileno(infp));
 	}
+#ifdef getc_unlocked			/* avoid stupid semaphores */
+	flockfile(infp);
+#endif
 	SET_FILE_BINARY(infp);
 					/* get header */
 	if (checkheader(infp, OCTFMT, load&IO_INFO ? stdout : (FILE *)NULL) < 0)
@@ -87,6 +93,11 @@ readoct(				/* read in octree file or stream */
 			readobj(sbuf);
 		if (load & IO_FILES)
 			ofn[nf] = savqstr(sbuf);
+		if (oct_t > last_it) {
+			time_t	t = fdate(sbuf);
+			if (t > last_it)
+				last_it = t;
+		}
 		nf++;
 	}
 	if (load & IO_FILES)
@@ -111,7 +122,7 @@ readoct(				/* read in octree file or stream */
 		if (nobjects != objorig+fnobjects)
 			octerror(USER, "bad object count; octree stale?");
 				/* check for non-surfaces */
-		if (nonsurfintree(scene->cutree))
+		if (oct_t <= last_it && nonsurfintree(scene->cutree))
 			octerror(USER, "modifier in tree; octree stale?");
 	    }
 	}
@@ -120,6 +131,10 @@ readoct(				/* read in octree file or stream */
 		pclose(infp);
 	else if (infp != stdin)
 		fclose(infp);
+#ifdef getc_unlocked
+	else
+		funlockfile(infp);
+#endif
 	return(nf);
 }