diff --git a/core/client.c b/core/client.c
index 8dcd542..1227cd6 100644
--- a/core/client.c
+++ b/core/client.c
@@ -105,3 +105,5 @@ void ipc_clients_free (struct ipc_clients *ap)
     }
     ap->size = 0;
 }
+
+
diff --git a/core/client.h b/core/client.h
index 51cebf2..08d663c 100644
--- a/core/client.h
+++ b/core/client.h
@@ -1,5 +1,5 @@
-#ifndef __IPC_PROCESS_H__
-#define __IPC_PROCESS_H__
+#ifndef __IPC_CLIENT_H__
+#define __IPC_CLIENT_H__
 
 struct ipc_client {
     unsigned int version;
diff --git a/core/communication.c b/core/communication.c
index ed0cd01..02b158f 100644
--- a/core/communication.c
+++ b/core/communication.c
@@ -210,3 +210,78 @@ int ipc_server_select (struct ipc_clients *clients, struct ipc_service *srv
 
 	return 0;
 }
+
+/*calculer le max filedescriptor*/
+static int getMaxFdServices(struct ipc_services *services)
+{
+    int i;
+    int max = 0;
+
+    for (i = 0; i < services->size; i++ ) {
+        if (services->services[i]->service_fd > max) {
+            max = services->services[i]->service_fd;
+        } 
+    }
+
+    return max;
+}
+
+/*
+ * ipc_application_select prend en parametre
+ *  * un tableau de server qu'on écoute
+ *  * le service qui attend de nouvelles connexions
+ *  * un tableau de client qui souhaitent parler
+ *
+ *  0 = OK
+ * -1 = error
+ */
+
+int ipc_application_select (struct ipc_services *services, struct ipc_services *active_services)
+{
+    assert (services != NULL);
+    assert (active_services != NULL);
+
+    // delete previous read active_services array
+    ipc_services_free (active_services);
+
+    int i, j;
+    /* master file descriptor list */
+    fd_set master;
+    fd_set readf;
+
+    /* maximum file descriptor number */
+    int fdmax;
+
+    /* clear the master and temp sets */
+    FD_ZERO(&master);
+    FD_ZERO(&readf);
+
+    for (i=0; i < services->size; i++) {
+        FD_SET(services->services[i]->service_fd, &master);
+    }
+
+    /* keep track of the biggest file descriptor */
+    fdmax = getMaxFdServices(services);
+
+	// printf ("loop ipc_server_select main_loop\n");
+	readf = master;
+	if(select(fdmax+1, &readf, NULL, NULL, NULL) == -1) {
+		perror("select");
+		return -1;
+	}
+
+	/*run through the existing connections looking for data to be read*/
+	for (i = 0; i <= fdmax; i++) {
+		// printf ("loop ipc_server_select inner loop\n");
+		if (FD_ISSET(i, &readf)) {
+			for(j = 0; j < services->size; j++) {
+				// printf ("loop ipc_server_select inner inner loop\n");
+				if(i == services->services[j]->service_fd ) {
+					ipc_service_add (active_services, services->services[j]);
+				}
+			}
+		}
+	}
+
+	return 0;
+}
diff --git a/core/communication.h b/core/communication.h
index 7fdd90c..bc6e2a7 100644
--- a/core/communication.h
+++ b/core/communication.h
@@ -45,6 +45,6 @@ int ipc_application_close (struct ipc_service *);
 int ipc_application_read (struct ipc_service *srv, struct ipc_message *m);
 int ipc_application_write (struct ipc_service *, const struct ipc_message *m);
 
-
+int ipc_application_select (struct ipc_services *services, struct ipc_services *active_services);
 
 #endif
diff --git a/core/usocket.c b/core/usocket.c
index 794e194..2d61714 100644
--- a/core/usocket.c
+++ b/core/usocket.c
@@ -259,3 +259,107 @@ int usock_remove (const char *path)
 {
     return unlink (path);
 }
+
+
+// TODO: ipc_services functions
+
+struct ipc_service * ipc_client_server_copy (const struct ipc_service *p)
+{
+    if (p == NULL)
+        return NULL;
+
+    struct ipc_service * copy = malloc (sizeof(struct ipc_service));
+    memset (copy, 0, sizeof (struct ipc_service));
+    memcpy (copy, p, sizeof (struct ipc_service));
+
+    return copy;
+}
+
+int ipc_client_server_eq (const struct ipc_service *p1, const struct ipc_service *p2)
+{
+    return (p1->version == p2->version && p1->index == p2->index
+            && p1->service_fd == p2->service_fd && memcmp(p1->spath, p1->spath, PATH_MAX) == 0 );
+}
+
+void ipc_client_server_gen (struct ipc_service *p
+        , unsigned int index, unsigned int version)
+{
+    p->version = version;
+    p->index = index;
+}
+
+int ipc_service_add (struct ipc_services *services, struct ipc_service *p)
+{
+    assert(services != NULL);
+    assert(p != NULL);
+
+    services->size++;
+    services->services = realloc(services->services
+            , sizeof(struct ipc_service) * services->size);
+
+    if (services->services == NULL) {
+        return -1;
+    }
+
+    services->services[services->size - 1] = p;
+    return 0;
+}
+
+int ipc_service_del (struct ipc_services *services, struct ipc_service *p)
+{
+    assert(services != NULL);
+    assert(p != NULL);
+
+    if (services->services == NULL) {
+        return -1;
+    }
+
+    int i;
+    for (i = 0; i < services->size; i++) {
+        if (services->services[i] == p) {
+
+            services->services[i] = services->services[services->size-1];
+            services->size--;
+            if (services->size == 0) {
+                ipc_services_free (services);
+            }
+            else {
+                services->services = realloc(services->services
+                        , sizeof(struct ipc_service) * services->size);
+
+                if (services->services == NULL) {
+                    return -2;
+                }
+            }
+
+            return 0;
+        }
+    }
+
+    return -3;
+}
+
+void service_print (struct ipc_service *p)
+{
+    if (p != NULL)
+        printf ("client %d : index %d, version %d\n"
+                , p->service_fd, p->index, p->version);
+}
+
+void ipc_services_print (struct ipc_services *ap)
+{
+    int i;
+    for (i = 0; i < ap->size; i++) {
+        printf("%d : ", i);
+        service_print(ap->services[i]);
+    }
+}
+
+void ipc_services_free (struct ipc_services *ap)
+{
+    if (ap->services != NULL) {
+        free (ap->services);
+        ap->services = NULL;
+    }
+    ap->size = 0;
+}
diff --git a/core/usocket.h b/core/usocket.h
index 75bf4ee..49fe891 100644
--- a/core/usocket.h
+++ b/core/usocket.h
@@ -17,6 +17,11 @@ struct ipc_service {
     int service_fd;
 };
 
+struct ipc_services {
+	struct ipc_service ** services;
+	int size;
+};
+
 /**
  * for all functions: 0 ok, < 0 not ok
  */
@@ -50,4 +55,20 @@ int usock_remove (const char *path);
 
 static inline int ipc_service_empty (struct ipc_service *srv) { srv = srv; return 0 ;};
 
+
+// store and remove only pointers on allocated structures
+int ipc_service_add (struct ipc_services *, struct ipc_service *);
+int ipc_service_del (struct ipc_services *, struct ipc_service *);
+
+void ipc_services_print (struct ipc_services *);
+void ipc_services_free  (struct ipc_services *);
+
+struct ipc_service * ipc_client_server_copy (const struct ipc_service *p);
+int ipc_service_eq (const struct ipc_service *p1, const struct ipc_service *p2);
+// create the client service structure
+void ipc_client_server_gen (struct ipc_service *p
+        , unsigned int index, unsigned int version);
+
+void service_print (struct ipc_service *);
+
 #endif