Index: trunk/src/libcschem/concrete.c
===================================================================
--- trunk/src/libcschem/concrete.c	(revision 2466)
+++ trunk/src/libcschem/concrete.c	(revision 2467)
@@ -63,6 +63,7 @@
 	return ctype_names[typ];
 }
 
+static long next_uid;
 
 csch_sheet_t *csch_sheet_alloc(csch_project_t *parent)
 {
@@ -70,6 +71,7 @@
 	csch_sheet_t *sheet = calloc(sizeof(csch_sheet_t), 1);
 
 	sheet->parent = parent;
+	sheet->uid = next_uid++;
 	htsp_init(&sheet->comm_str, strhash, strkeyeq);
 
 	for(n = 0; n < CSCH_DSPLY_max; n++)
Index: trunk/src/libcschem/concrete.h
===================================================================
--- trunk/src/libcschem/concrete.h	(revision 2466)
+++ trunk/src/libcschem/concrete.h	(revision 2467)
@@ -175,6 +175,7 @@
 struct csch_sheet_s {
 	rnd_hidlib_t hidlib;
 	csch_project_t *parent;
+	long uid;
 
 	csch_rtree_t dsply[CSCH_DSPLY_max];     /* IDs in screen coords, per display layer */
 	csch_cgrp_t direct, indirect; /* a sheet is really made of groups to keep the code simple */
Index: trunk/src/libcschem/plug_library.c
===================================================================
--- trunk/src/libcschem/plug_library.c	(revision 2466)
+++ trunk/src/libcschem/plug_library.c	(revision 2467)
@@ -39,6 +39,7 @@
 #include "plug_library.h"
 
 static htsp_t lib_masters;
+static int master_uids = 0;
 
 
 TODO("librnd: Use libualloc")
@@ -195,6 +196,7 @@
 
 	res = calloc(sizeof(csch_lib_master_t), 1);
 	res->name = rnd_strdup(name);
+	res->uid = master_uids++;
 	htsp_init(&res->roots, strhash, strkeyeq);
 	htsp_set(&lib_masters, res->name, res);
 	return res;
Index: trunk/src/libcschem/plug_library.h
===================================================================
--- trunk/src/libcschem/plug_library.h	(revision 2466)
+++ trunk/src/libcschem/plug_library.h	(revision 2467)
@@ -87,6 +87,7 @@
 
 typedef struct csch_lib_master_s {
 	char *name;
+	int uid;
 	htsp_t roots;       /* realpath -> (csch_lib_t *) root dir */
 	vtp0_t backends;    /* list of (csch_lib_backend_t *) as registered */
 } csch_lib_master_t;