diff --git a/vm/debug.cpp b/vm/debug.cpp
index 3a8e847f14..1d2edbbf46 100755
--- a/vm/debug.cpp
+++ b/vm/debug.cpp
@@ -211,7 +211,7 @@ void factor_vm::dump_memory(cell from, cell to)
 		dump_cell(from);
 }
 
-void factor_vm::dump_zone(char *name, zone *z)
+void factor_vm::dump_zone(const char *name, zone *z)
 {
 	print_string(name); print_string(": ");
 	print_string("Start="); print_cell(z->start);
diff --git a/vm/vm.hpp b/vm/vm.hpp
index 73a423ccf4..ce2acfab45 100755
--- a/vm/vm.hpp
+++ b/vm/vm.hpp
@@ -301,7 +301,7 @@ struct factor_vm
 	void print_callstack();
 	void dump_cell(cell x);
 	void dump_memory(cell from, cell to);
-	void dump_zone(char *name, zone *z);
+	void dump_zone(const char *name, zone *z);
 	void dump_generations();
 	void dump_objects(cell type);
 	void find_data_references_step(cell *scan);