Index: /trunk/zoo-project/zoo-kernel/service_internal.c
===================================================================
--- /trunk/zoo-project/zoo-kernel/service_internal.c	(revision 629)
+++ /trunk/zoo-project/zoo-kernel/service_internal.c	(revision 630)
@@ -381,8 +381,11 @@
 
 #ifndef __APPLE__
+/**
+ * arg for semctl system calls. 
+ */
 union semun {
-  int val;
-  struct semid_ds *buf;
-  ushort *array;
+  int val; //!< value for SETVAL 
+  struct semid_ds *buf; //!< buffer for IPC_STAT & IPC_SET
+  ushort *array; //!< array for GETALL & SETALL
 };
 #endif
Index: /trunk/zoo-project/zoo-kernel/service_internal_ruby.h
===================================================================
--- /trunk/zoo-project/zoo-kernel/service_internal_ruby.h	(revision 629)
+++ /trunk/zoo-project/zoo-kernel/service_internal_ruby.h	(revision 630)
@@ -50,9 +50,12 @@
 
 #define MAX_ARGS 3
+/**
+ * The Ruby method pointer
+ */
 struct my_callback {
-  VALUE obj;
-  ID method_id;
-  int nargs;
-  VALUE args[MAX_ARGS];
+  VALUE obj; //!< Object used to call a method
+  ID method_id; //!< The method to call
+  int nargs; //!< The arguments number
+  VALUE args[MAX_ARGS]; //!< The arguments values
 };
 
Index: /trunk/zoo-project/zoo-kernel/ulinet.h
===================================================================
--- /trunk/zoo-project/zoo-kernel/ulinet.h	(revision 629)
+++ /trunk/zoo-project/zoo-kernel/ulinet.h	(revision 630)
@@ -66,4 +66,8 @@
 #endif
 
+  /**
+   * Headers storage
+   * @see header_write_data
+   */
   struct MemoryStruct {
     char *memory; //!< the memory space to store data