diff --git a/mxml.h b/mxml.h
index 0879da2..0061097 100644
--- a/mxml.h
+++ b/mxml.h
@@ -139,6 +139,7 @@ int mxml_parse_entity(char **buf, const char* file_name, char *error, int error_
 int mxml_print_tree(char *buffer, int *buffer_size, PMXML_NODE tree);
 void mxml_debug_tree(PMXML_NODE tree, int level);
 void mxml_free_tree(PMXML_NODE tree);
+int mxml_write_tree(const char *file_name, PMXML_NODE tree);
 
 void mxml_dirname(char* path);
 void mxml_basename(char *path);