Index: branches/1.2/mem.h
===================================================================
--- branches/1.2/mem.h	(revision 303)
+++ branches/1.2/mem.h	(revision 380)
@@ -1,4 +1,17 @@
-typedef struct _xc_mem_t xc_mem_t;
-typedef struct _xc_block_t xc_block_t;
+typedef struct _xc_mem_handlers_t xc_mem_handlers_t;
+
+#ifndef XC_MEM_IMPL
+struct _xc_mem_t {
+	const xc_mem_handlers_t *handlers;
+	xc_shm_t                *shm;
+};
+#   define XC_MEM_IMPL _xc_mem_t
+#endif
+
+#ifndef XC_MEMBLOCK_IMPL
+#   define XC_MEMBLOCK_IMPL _xc_block_t
+#endif
+typedef struct XC_MEM_IMPL xc_mem_t;
+typedef struct XC_MEMBLOCK_IMPL xc_block_t;
 typedef unsigned int xc_memsize_t;
 
@@ -38,5 +51,5 @@
 }
 
-typedef struct {
+struct _xc_mem_handlers_t {
 	XC_MEM_MALLOC((*malloc));
 	XC_MEM_FREE((*free));
@@ -54,12 +67,5 @@
 	XC_MEM_INIT((*init));
 	XC_MEM_DESTROY((*destroy));
-} xc_mem_handlers_t;
-
-#ifndef XC_MEM_IMPL
-struct _xc_mem_t {
-	const xc_mem_handlers_t *handlers;
-	xc_shm_t                *shm;
 };
-#endif
 
 int xc_mem_scheme_register(const char *name, const xc_mem_handlers_t *handlers);