Index: apps/app_macro.c
===================================================================
--- apps/app_macro.c	(revision 162018)
+++ apps/app_macro.c	(working copy)
@@ -103,7 +103,31 @@
 static char *exclusive_synopsis = "Exclusive Macro Implementation";
 static char *exit_synopsis = "Exit From Macro";
 
+static void macro_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
 
+struct ast_datastore_info macro_ds_info = {
+	.type = "MACRO",
+	.chan_fixup = macro_fixup,
+};
+
+static void macro_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan)
+{
+	int i;
+	char varname[10];
+	pbx_builtin_setvar_helper(new_chan, "MACRO_DEPTH", "0");
+	pbx_builtin_setvar_helper(new_chan, "MACRO_CONTEXT", NULL);
+	pbx_builtin_setvar_helper(new_chan, "MACRO_EXTEN", NULL);
+	pbx_builtin_setvar_helper(new_chan, "MACRO_PRIORITY", NULL);
+	pbx_builtin_setvar_helper(new_chan, "MACRO_OFFSET", NULL);
+	for (i = 1; i < 100; i++) {
+		snprintf(varname, sizeof(varname), "ARG%d", i);
+		while (pbx_builtin_getvar_helper(new_chan, varname)) {
+			/* Kill all levels of arguments */
+			pbx_builtin_setvar_helper(new_chan, varname, NULL);
+		}
+	}
+}
+
 static struct ast_exten *find_matching_priority(struct ast_context *c, const char *exten, int priority, const char *callerid)
 {
 	struct ast_exten *e;
@@ -165,6 +189,7 @@
 	char *save_macro_priority;
 	char *save_macro_offset;
 	struct ast_module_user *u;
+	struct ast_datastore *macro_store = ast_channel_datastore_find(chan, &macro_ds_info, NULL);
  
 	if (ast_strlen_zero(data)) {
 		ast_log(LOG_WARNING, "Macro() requires arguments. See \"show application macro\" for help.\n");
@@ -173,6 +198,19 @@
 
 	u = ast_module_user_add(chan);
 
+	do {
+		if (macro_store) {
+			break;
+		}
+		if (!(macro_store = ast_channel_datastore_alloc(&macro_ds_info, NULL))) {
+			ast_log(LOG_WARNING, "Unable to allocate new datastore.\n");
+			break;
+		}
+		/* Just the existence of this datastore is enough. */
+		macro_store->inheritance = DATASTORE_INHERIT_FOREVER;
+		ast_channel_datastore_add(chan, macro_store);
+	} while (0);
+
 	/* does the user want a deeper rabbit hole? */
 	s = pbx_builtin_getvar_helper(chan, "MACRO_RECURSION");
 	if (s)