diff --git a/calma/CalmaWrite.c b/calma/CalmaWrite.c
index bb1134b4..920b9b02 100644
--- a/calma/CalmaWrite.c
+++ b/calma/CalmaWrite.c
@@ -53,12 +53,13 @@ static char rcsid[] __attribute__ ((unused)) ="$Header: /usr/cvsroot/magic-8.0/c
 #include "utils/stack.h"
 
     /* Exports */
-bool CalmaDoLibrary = FALSE;	 /* If TRUE, do not output the top level */
-bool CalmaDoLabels = TRUE;	 /* If FALSE, don't output labels with GDS-II */
-bool CalmaDoLower = TRUE;	 /* If TRUE, allow lowercase labels. */
-bool CalmaFlattenArrays = FALSE; /* If TRUE, output arrays as individual uses */
-bool CalmaAddendum = FALSE;	 /* If TRUE, do not output readonly cell defs */
-bool CalmaNoDateStamp = FALSE;	 /* If TRUE, output zero for creation date stamp */
+bool CalmaDoLibrary = FALSE;	  /* If TRUE, do not output the top level */
+bool CalmaDoLabels = TRUE;	  /* If FALSE, don't output labels with GDS-II */
+bool CalmaDoLower = TRUE;	  /* If TRUE, allow lowercase labels. */
+bool CalmaFlattenArrays = FALSE;  /* If TRUE, output arrays as individual uses */
+bool CalmaAddendum = FALSE;	  /* If TRUE, do not output readonly cell defs */
+bool CalmaNoDateStamp = FALSE;	  /* If TRUE, output zero for creation date stamp */
+bool CalmaAllowUndefined = FALSE; /* If TRUE, allow calls to undefined cells */
 
     /* Experimental stuff---not thoroughly tested (as of Sept. 2007)! */
 bool CalmaContactArrays = FALSE; /* If TRUE, output contacts as subcell arrays */
@@ -305,7 +306,12 @@ CalmaWrite(rootDef, f)
      */
 
     dummy.cu_def = rootDef;
-    DBCellReadArea(&dummy, &rootDef->cd_bbox);
+    if (DBCellReadArea(&dummy, &rootDef->cd_bbox, !CalmaAllowUndefined))
+    {
+	TxError("Failure to read entire subtree of the cell.\n");
+	return FALSE;
+    }
+
     DBFixMismatch();
 
     /*
diff --git a/calma/calma.h b/calma/calma.h
index 0762f81a..d37d50f3 100644
--- a/calma/calma.h
+++ b/calma/calma.h
@@ -41,6 +41,7 @@ extern char **CalmaFlattenUsesByName;
 extern bool CalmaReadOnly;
 extern bool CalmaContactArrays;
 extern bool CalmaPostOrder;
+extern bool CalmaAllowUndefined;
 
 /* Externally-visible procedures: */
 extern bool CalmaWrite();
diff --git a/cif/CIFwrite.c b/cif/CIFwrite.c
index 8f40c2b2..0dbfcc67 100644
--- a/cif/CIFwrite.c
+++ b/cif/CIFwrite.c
@@ -132,14 +132,18 @@ CIFWrite(rootDef, f)
      */
 
     dummy.cu_def = rootDef;
-    DBCellReadArea(&dummy, &rootDef->cd_bbox);
+    if (DBCellReadArea(&dummy, &rootDef->cd_bbox, TRUE))
+    {
+	TxError("Failure to read in entire subtree of the cell.\n");
+	return (FALSE);
+    }
     DBFixMismatch();
 
     if (CIFCurStyle->cs_reducer == 0)
     {
 	TxError("The current CIF output style can only be used for writing\n");
 	TxError("Calma output.  Try picking another output style.\n");
-	return (TRUE);
+	return (FALSE);
     }
 
     /*
diff --git a/commands/CmdCD.c b/commands/CmdCD.c
index a4a2efb7..75326603 100644
--- a/commands/CmdCD.c
+++ b/commands/CmdCD.c
@@ -109,6 +109,7 @@ bool cmdDumpParseArgs();
 #define CALMA_WRITE	18
 #define CALMA_POLYS	19
 #define CALMA_PATHS	20
+#define CALMA_UNDEFINED	21
 
 #define CALMA_WARN_HELP CIF_WARN_END	/* undefined by CIF module */
 
@@ -127,6 +128,7 @@ CmdCalma(w, cmd)
     static char *gdsExts[] = {".gds", ".gds2", ".strm", "", NULL};
     static char *cmdCalmaYesNo[] = {
 		"no", "false", "off", "0", "yes", "true", "on", "1", 0 };
+    static char *cmdCalmaAllowDisallow[] = {"disallow", "0", "allow", "1", 0};
     static char *cmdCalmaWarnOptions[] = { "default", "none", "align",
 		"limit", "redirect", "help", 0 };
     static char *cmdCalmaOption[] =
@@ -156,6 +158,8 @@ CmdCalma(w, cmd)
 	"		put non-Manhattan polygons into subcells",
 	"path subcells [yes|no]\n"
 	"		put wire paths into individual subcells",
+	"undefined [allow|disallow]\n"
+	"		[dis]allow writing of GDS with calls to undefined cells",
 	NULL
     };
 
@@ -279,6 +283,26 @@ CmdCalma(w, cmd)
 	    CalmaAddendum = (option < 4) ? FALSE : TRUE;
 	    return;
 
+	case CALMA_UNDEFINED:
+	    if (cmd->tx_argc == 2)
+	    {
+#ifdef MAGIC_WRAPPER
+		Tcl_SetObjResult(magicinterp, Tcl_NewBooleanObj(CalmaAllowUndefined));
+#else
+		TxPrintf("Writing of GDS file with undefined cells is %sallowed.\n",
+			(CalmaAllowUndefined) ?  "" : "dis");
+#endif
+		return;
+	    }
+	    else if (cmd->tx_argc != 3)
+		goto wrongNumArgs;
+
+	    option = Lookup(cmd->tx_argv[2], cmdCalmaAllowDisallow);
+	    if (option < 0)
+		goto wrongNumArgs;
+	    CalmaAllowUndefined = (option < 2) ? FALSE : TRUE;
+	    return;
+
 	case CALMA_CONTACTS:
 	    if (cmd->tx_argc == 2)
 	    {
diff --git a/database/DBexpand.c b/database/DBexpand.c
index 63d0f7d1..f93aaa67 100644
--- a/database/DBexpand.c
+++ b/database/DBexpand.c
@@ -275,7 +275,8 @@ dbUnexpandFunc(scx, arg)
  * the given rectangle.
  *
  * Results:
- *	None.
+ *	If "halt_on_error" is TRUE, then return 1 if any subcell could not
+ *	be read.  Otherwise, return 0.
  *
  * Side effects:
  *	May make new cells known to the database.  Sets the CDAVAILABLE
@@ -284,10 +285,11 @@ dbUnexpandFunc(scx, arg)
  * ----------------------------------------------------------------------------
  */
 
-void
-DBCellReadArea(rootUse, rootRect)
+int
+DBCellReadArea(rootUse, rootRect, halt_on_error)
     CellUse *rootUse;	/* Root cell use from which search begins */
     Rect *rootRect;	/* Area to be read, in root coordinates */
+    bool halt_on_error;	/* If TRUE, failure to find a cell causes a halt */
 {
     int dbReadAreaFunc();
     SearchContext scontext;
@@ -295,30 +297,39 @@ DBCellReadArea(rootUse, rootRect)
     scontext.scx_use = rootUse;
     scontext.scx_trans = GeoIdentityTransform;
     scontext.scx_area = *rootRect;
-    (void) dbReadAreaFunc(&scontext);
+    if (dbReadAreaFunc(&scontext, halt_on_error) == 1)
+	return 1;
+
+    return 0;
 }
 
 int
-dbReadAreaFunc(scx)
+dbReadAreaFunc(scx, halt_on_error)
     SearchContext *scx;	/* Pointer to context specifying
 					 * the cell use to be read in, and
 					 * an area to be recursively read in
 					 * coordinates of the cell use's def.
 					 */
+    bool halt_on_error;	/* If TURE, failure to find a cell causes a halt */
 {
     CellDef *def = scx->scx_use->cu_def;
 
     if ((def->cd_flags & CDAVAILABLE) == 0)
     {
 	bool dereference = (def->cd_flags & CDDEREFERENCE) ? TRUE : FALSE;
-	(void) DBCellRead(def, (char *) NULL, TRUE, dereference, NULL);
+	if (DBCellRead(def, (char *)NULL, TRUE, dereference, NULL) == FALSE)
+	    if (halt_on_error)
+		return 1;
+
 	/* Note: we don't have to invoke DBReComputeBbox here because
 	 * if the bbox changed then there was a timestamp mismatch and
 	 * the timestamp code will take care of the bounding box later.
 	 */
     }
 
-    (void) DBCellSrArea(scx, dbReadAreaFunc, (ClientData) NULL);
+    if (DBCellSrArea(scx, dbReadAreaFunc, (ClientData)halt_on_error))
+	if (halt_on_error)
+	    return 1;
 
     /* Be clever about handling arrays:  if the search area covers this
      * whole definition, then there's no need to look at any other
@@ -328,5 +339,6 @@ dbReadAreaFunc(scx)
 
     if (GEO_SURROUND(&scx->scx_area, &scx->scx_use->cu_def->cd_bbox))
 	return 2;
+
     return 0;
 }
diff --git a/database/DBio.c b/database/DBio.c
index df5927f6..56874065 100644
--- a/database/DBio.c
+++ b/database/DBio.c
@@ -899,7 +899,7 @@ DBReadBackup(name)
  *
  * DBCellRead --
  *
- * This is the wrapper for DBCellReadDef.  The routine has been divided into
+ * This is the wrapper for dbCellReadDef.  The routine has been divided into
  * parts so that a single backup file can be made and recovered, and in
  * preparation for allowing certain cell definitions to be in-lined into the
  * output file (such as polygonXXXXX cells generated by the gds read-in).
@@ -2947,7 +2947,8 @@ DBCellWrite(cellDef, fileName)
 	{
 	    bool dereference = (cellDef->cd_flags & CDDEREFERENCE) ? TRUE : FALSE;
 	    /* Re-aquire the lock on the new file by opening it. */
-	    DBCellRead(cellDef, NULL, TRUE, dereference, NULL);
+	    if (DBCellRead(cellDef, NULL, TRUE, dereference, NULL) == FALSE)
+		return FALSE;
 	}
 #endif
 
diff --git a/database/database.h.in b/database/database.h.in
index 0815c75f..5b02ed8c 100644
--- a/database/database.h.in
+++ b/database/database.h.in
@@ -720,7 +720,7 @@ extern bool DBCellRead();
 extern bool DBTestOpen();
 extern char *DBGetTech();
 extern bool DBCellWrite();
-extern void DBCellReadArea();
+extern int DBCellReadArea();
 extern void DBFileRecovery();
 extern bool DBWriteBackup();
 extern bool DBReadBackup();
diff --git a/drc/DRCmain.c b/drc/DRCmain.c
index 59edd41b..6fa55e7c 100644
--- a/drc/DRCmain.c
+++ b/drc/DRCmain.c
@@ -664,7 +664,11 @@ DRCCheck(use, area)
     SearchContext scx;
     extern int drcCheckFunc();	/* Forward reference. */
 
-    DBCellReadArea(use, area);
+    if (DBCellReadArea(use, area, TRUE))
+    {
+	TxError("Failure to read in entire subtree of cell.\n");
+	return;
+    }
 
     scx.scx_use = use;
     scx.scx_x = use->cu_xlo;
diff --git a/extract/ExtMain.c b/extract/ExtMain.c
index 8b8e75f6..d3b0c4f5 100644
--- a/extract/ExtMain.c
+++ b/extract/ExtMain.c
@@ -179,7 +179,11 @@ ExtAll(rootUse)
     CellUse *rootUse;
 {
     /* Make sure the entire subtree is read in */
-    DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox);
+    if (DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox, TRUE))
+    {
+	TxError("Failure to read entire subtree of cell.\n");
+	return;
+    }
 
     /* Fix up bounding boxes if they've changed */
     DBFixMismatch();
@@ -264,7 +268,11 @@ ExtUnique(rootUse, option)
     int nwarn;
 
     /* Make sure the entire subtree is read in */
-    DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox);
+    if (DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox, TRUE))
+    {
+	TxError("Failure to read entire subtree of cell.\n");
+	return;
+    }
 
     /* Fix up bounding boxes if they've changed */
     DBFixMismatch();
@@ -526,7 +534,11 @@ ExtIncremental(rootUse)
     CellUse *rootUse;
 {
     /* Make sure the entire subtree is read in */
-    DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox);
+    if (DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox, TRUE))
+    {
+	TxError("Failure to read entire subtree of cell.\n");
+	return;
+    }
 
     /* Fix up bounding boxes if they've changed */
     DBFixMismatch();
diff --git a/extract/ExtTimes.c b/extract/ExtTimes.c
index 262b2bfe..c13c5f59 100644
--- a/extract/ExtTimes.c
+++ b/extract/ExtTimes.c
@@ -169,7 +169,11 @@ ExtTimes(rootUse, f)
     HashEntry *he;
 
     /* Make sure this cell is read in */
-    DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox);
+    if (DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox, TRUE))
+    {
+	TxError("Failure to read entire subtree of cell.\n");
+	return;
+    }
 
     /* Initialize cumulative statistics */
     extCumInit(&cumFetsPerSecPaint);
@@ -1020,7 +1024,11 @@ ExtInterCount(rootUse, halo, f)
     double inter;
 
     /* Make sure this cell is read in */
-    DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox);
+    if (DBCellReadArea(rootUse, &rootUse->cu_def->cd_bbox, TRUE))
+    {
+	TxError("Failure to read entire subtree of cell.\n");
+	return;
+    }
 
     /* Initialize cumulative statistics */
     extCumInit(&cumPercentInteraction);
diff --git a/garouter/gaTest.c b/garouter/gaTest.c
index b48c78d5..a6f2fd70 100644
--- a/garouter/gaTest.c
+++ b/garouter/gaTest.c
@@ -201,7 +201,7 @@ GAGenChans(chanType, area, f)
     }
 
     /* Make sure everything in 'area' is read */
-    (void) DBCellReadArea(EditCellUse, area);
+    (void) DBCellReadArea(EditCellUse, area, FALSE);
     DBFixMismatch();
 
     /* Start with a clean slate */
diff --git a/lef/lefWrite.c b/lef/lefWrite.c
index a8adc57e..17a3ac17 100644
--- a/lef/lefWrite.c
+++ b/lef/lefWrite.c
@@ -1982,7 +1982,11 @@ LefWriteAll(rootUse, writeTopCell, lefTech, lefHide, lefTopLayer, lefDoMaster, r
     rootdef = rootUse->cu_def;
 
     /* Make sure the entire subtree is read in */
-    DBCellReadArea(rootUse, &rootdef->cd_bbox);
+    if (DBCellReadArea(rootUse, &rootdef->cd_bbox, TRUE))
+    {
+	TxError("Could not read entire subtree of the cell.\n");
+	return;
+    }
 
     /* Fix up bounding boxes if they've changed */
     DBFixMismatch();