+ *
+ * Sometimes, the situation is even more complicated: There is some shared
+ * messages that you want to see from every file, and some private messages
+ * that you want to be defined only in one C file.
+ * In that case, use the previous trick for common messages, and use
+ * #GRAS_DEFINE_TYPE_LOCAL for the private messages.
+ *
+ * For now, there is no way to have semi-private symbols (for example shared
+ * in all files of a library), sorry. Use functions as interface to your
+ * library instead of publishing directly the messages.