diff --git a/common/os_calls.c b/common/os_calls.c
index 211adc82..80e5bad3 100644
--- a/common/os_calls.c
+++ b/common/os_calls.c
@@ -1069,28 +1069,39 @@ g_obj_wait(tbus* read_objs, int rcount, tbus* write_objs, int wcount,
     ptime = &time;
   }
   FD_ZERO(&rfds);
-  FD_ZERO(&wfds);
-  for (i = 0; i < rcount; i++)
-  {
-    sck = (int)(read_objs[i]);
-    if (sck > 0) {
-      FD_SET(sck, &rfds);
-      if (sck > max)
-      {
-        max = sck;
+  FD_ZERO(&wfds);  
+  /*Find the highest descriptor number in read_obj */
+  if(read_objs!=NULL){
+    for (i = 0; i < rcount; i++)
+    {
+      sck = (int)(read_objs[i]);
+      if (sck > 0) {
+        FD_SET(sck, &rfds);
+        if (sck > max)
+        {
+	  max = sck; /*max holds the highest socket/descriptor number */ 
+        }
       }
     }
+  }else if(rcount>0){
+      g_writeln("Programming error read_objs is null");
+      return 1; /*error*/
   }
-  for (i = 0; i < wcount; i++)
-  {
-    sck = (int)(write_objs[i]);
-    if (sck > 0) {
-      FD_SET(sck, &wfds);
-      if (sck > max)
-      {
-        max = sck;
+  if(write_objs!=NULL){
+    for (i = 0; i < wcount; i++)
+    {
+      sck = (int)(write_objs[i]);
+      if (sck > 0) {
+        FD_SET(sck, &wfds);
+        if (sck > max)
+        {
+          max = sck; /*max holds the highest socket/descriptor number */ 
+        }
       }
     }
+  }else if(wcount>0){
+      g_writeln("Programming error write_objs is null");
+      return 1; /*error*/
   }
   res = select(max + 1, &rfds, &wfds, 0, ptime);
   if (res < 0)
@@ -1103,7 +1114,7 @@ g_obj_wait(tbus* read_objs, int rcount, tbus* write_objs, int wcount,
     {
       return 0;
     }
-    return 1;
+    return 1; /*error*/
   }
   return 0;
 #endif
diff --git a/common/trans.c b/common/trans.c
index 377b90ba..6b762d00 100644
--- a/common/trans.c
+++ b/common/trans.c
@@ -69,7 +69,7 @@ trans_delete(struct trans* self)
 
 /*****************************************************************************/
 int APP_CC
-trans_get_wait_objs(struct trans* self, tbus* objs, int* count, int* timeout)
+trans_get_wait_objs(struct trans* self, tbus* objs, int* count)
 {
   if (self == 0)
   {
diff --git a/common/trans.h b/common/trans.h
index bb0f42c0..8e8d942a 100644
--- a/common/trans.h
+++ b/common/trans.h
@@ -64,7 +64,7 @@ trans_create(int mode, int in_size, int out_size);
 void APP_CC
 trans_delete(struct trans* self);
 int APP_CC
-trans_get_wait_objs(struct trans* self, tbus* objs, int* count, int* timeout);
+trans_get_wait_objs(struct trans* self, tbus* objs, int* count);
 int APP_CC
 trans_check_wait_objs(struct trans* self);
 int APP_CC
diff --git a/sesman/chansrv/chansrv.c b/sesman/chansrv/chansrv.c
index f2ca961d..e9d596cf 100644
--- a/sesman/chansrv/chansrv.c
+++ b/sesman/chansrv/chansrv.c
@@ -447,7 +447,7 @@ channel_thread_loop(void* in_val)
     num_objs = 0;
     objs[num_objs] = g_term_event;
     num_objs++;
-    trans_get_wait_objs(g_lis_trans, objs, &num_objs, &timeout);
+    trans_get_wait_objs(g_lis_trans, objs, &num_objs);
     while (g_obj_wait(objs, num_objs, 0, 0, timeout) == 0)
     {
       if (g_is_wait_obj_set(g_term_event))
@@ -492,8 +492,8 @@ channel_thread_loop(void* in_val)
       num_objs = 0;
       objs[num_objs] = g_term_event;
       num_objs++;
-      trans_get_wait_objs(g_lis_trans, objs, &num_objs, &timeout);
-      trans_get_wait_objs(g_con_trans, objs, &num_objs, &timeout);
+      trans_get_wait_objs(g_lis_trans, objs, &num_objs);
+      trans_get_wait_objs(g_con_trans, objs, &num_objs);
       clipboard_get_wait_objs(objs, &num_objs, &timeout);
       sound_get_wait_objs(objs, &num_objs, &timeout);
       dev_redir_get_wait_objs(objs, &num_objs, &timeout);
diff --git a/xrdp/xrdp.c b/xrdp/xrdp.c
index 95936cef..ac2aae45 100644
--- a/xrdp/xrdp.c
+++ b/xrdp/xrdp.c
@@ -22,6 +22,8 @@
 
 #include "xrdp.h"
 
+#define THREAD_WAITING 100
+
 static struct xrdp_listen* g_listen = 0;
 static long g_threadid = 0; /* main threadid */
 
@@ -37,6 +39,9 @@ static long g_sync_param2 = 0;
 static long (*g_sync_func)(long param1, long param2);
 
 /*****************************************************************************/
+/* This function is used to run a function from the main thread.
+   Sync_func is the function pointer that will run from main thread
+   The function can have two long in parameters and must return long */
 long APP_CC
 g_xrdp_sync(long (*sync_func)(long param1, long param2), long sync_param1,
             long sync_param2)
@@ -44,32 +49,46 @@ g_xrdp_sync(long (*sync_func)(long param1, long param2), long sync_param1,
   long sync_result;
   int sync_command;
 
+  /* If the function is called from the main thread, the function can 
+   * be called directly. g_threadid= main thread ID*/
   if (tc_threadid_equal(tc_get_threadid(), g_threadid))
   {
     /* this is the main thread, call the function directly */
     /* in fork mode, this always happens too */
     sync_result = sync_func(sync_param1, sync_param2);
+    /*g_writeln("g_xrdp_sync processed IN main thread -> continue");*/
   }
   else
   {
+    /* All threads have to wait here until the main thread 
+     * process the function. g_process_waiting_function() is called 
+     * from the listening thread. g_process_waiting_function() process the function*/  
     tc_mutex_lock(g_sync1_mutex);
     tc_mutex_lock(g_sync_mutex);
     g_sync_param1 = sync_param1;
     g_sync_param2 = sync_param2;
     g_sync_func = sync_func;
-    g_sync_command = 100;
+    /* set a value THREAD_WAITING so the g_process_waiting_function function 
+     * know if any function must be processed */
+    g_sync_command = THREAD_WAITING; 
     tc_mutex_unlock(g_sync_mutex);
-    g_set_wait_obj(g_sync_event);
+    /* set this event so that the main thread know if 
+     * g_process_waiting_function() must be called */
+    g_set_wait_obj(g_sync_event); 
     do
     {
       g_sleep(100);
       tc_mutex_lock(g_sync_mutex);
-      sync_command = g_sync_command;
+      /* load new value from global to see if the g_process_waiting_function() 
+       * function has processed the function */
+      sync_command = g_sync_command; 
       sync_result = g_sync_result;
       tc_mutex_unlock(g_sync_mutex);
     }
-    while (sync_command != 0);
+    while (sync_command != 0); /* loop until g_process_waiting_function() 
+				* has processed the request*/
     tc_mutex_unlock(g_sync1_mutex);
+    /*g_writeln("g_xrdp_sync processed BY main thread -> continue");*/
   }
   return sync_result;
 }
@@ -159,15 +178,17 @@ pipe_sig(int sig_num)
 }
 
 /*****************************************************************************/
+/*Some function must be called from the main thread.
+ if g_sync_command==THREAD_WAITING a function is waiting to be processed*/
 void APP_CC
-g_loop(void)
+g_process_waiting_function(void)
 {
   tc_mutex_lock(g_sync_mutex);
   if (g_sync_command != 0)
   {
     if (g_sync_func != 0)
     {
-      if (g_sync_command == 100)
+      if (g_sync_command == THREAD_WAITING)
       {
         g_sync_result = g_sync_func(g_sync_param1, g_sync_param2);
       }
@@ -464,13 +485,17 @@ main(int argc, char** argv)
   pid = g_getpid();
   g_snprintf(text, 255, "xrdp_%8.8x_main_term", pid);
   g_term_event = g_create_wait_obj(text);
-  g_snprintf(text, 255, "xrdp_%8.8x_main_sync", pid);
-  g_sync_event = g_create_wait_obj(text);
   if (g_term_event == 0)
   {
     g_writeln("error creating g_term_event");
   }
-  g_listen->startup_params = startup_params;
+  g_snprintf(text, 255, "xrdp_%8.8x_main_sync", pid);
+  g_sync_event = g_create_wait_obj(text);
+  if (g_sync_event == 0)
+  {
+    g_writeln("error creating g_sync_event");
+  }
+  g_listen->startup_params = startup_params;  
   xrdp_listen_main_loop(g_listen);
   xrdp_listen_delete(g_listen);
   tc_mutex_delete(g_sync_mutex);
diff --git a/xrdp/xrdp.h b/xrdp/xrdp.h
index 0bc4a24d..2ef81659 100644
--- a/xrdp/xrdp.h
+++ b/xrdp/xrdp.h
@@ -52,7 +52,7 @@ g_get_term_event(void);
 tbus APP_CC
 g_get_sync_event(void);
 void APP_CC
-g_loop(void);
+g_process_waiting_function(void);
 
 /* xrdp_cache.c */
 struct xrdp_cache* APP_CC
diff --git a/xrdp/xrdp_listen.c b/xrdp/xrdp_listen.c
index bbdd729a..b79ce1c2 100644
--- a/xrdp/xrdp_listen.c
+++ b/xrdp/xrdp_listen.c
@@ -37,6 +37,10 @@ xrdp_listen_create_pro_done(struct xrdp_listen* self)
   pid = g_getpid();
   g_snprintf(text, 255, "xrdp_%8.8x_listen_pro_done_event", pid);
   self->pro_done_event = g_create_wait_obj(text);
+  if(self->pro_done_event == 0)
+  {
+    g_writeln("Failure creating pro_done_event");
+  }
   return 0;
 }
 
@@ -295,7 +299,7 @@ xrdp_listen_main_loop(struct xrdp_listen* self)
   {
     self->listen_trans->trans_conn_in = xrdp_listen_conn_in;
     self->listen_trans->callback_data = self;
-    term_obj = g_get_term_event();
+    term_obj = g_get_term_event(); /*Global termination event */
     sync_obj = g_get_sync_event();
     done_obj = self->pro_done_event;
     cont = 1;
@@ -307,31 +311,33 @@ xrdp_listen_main_loop(struct xrdp_listen* self)
       robjs[robjs_count++] = sync_obj;
       robjs[robjs_count++] = done_obj;
       timeout = -1;
-      if (trans_get_wait_objs(self->listen_trans, robjs, &robjs_count,
-                              &timeout) != 0)
+      if (trans_get_wait_objs(self->listen_trans, robjs, &robjs_count) != 0)
       {
+	g_writeln("Listening socket is in wrong state we terminate listener") ;
         break;
       }
-      /* wait */
+      /* wait - timeout -1 means wait indefinitely*/
       if (g_obj_wait(robjs, robjs_count, 0, 0, timeout) != 0)
       {
         /* error, should not get here */
         g_sleep(100);
       }
-      if (g_is_wait_obj_set(term_obj)) /* term */
+      if (g_is_wait_obj_set(term_obj)) /* termination called */
       {
         break;
       }
-      if (g_is_wait_obj_set(sync_obj)) /* sync */
+      if (g_is_wait_obj_set(sync_obj)) /* some function must be processed by this thread */
       {
         g_reset_wait_obj(sync_obj);
-        g_loop();
+        g_process_waiting_function(); /* run the function */
       }
       if (g_is_wait_obj_set(done_obj)) /* pro_done_event */
       {
-        g_reset_wait_obj(done_obj);
+        g_reset_wait_obj(done_obj); 
+	/* a process has died remove it from lists*/
         xrdp_listen_delete_done_pro(self);
       }
+      /* Run the callback when accept() returns a new socket*/
       if (trans_check_wait_objs(self->listen_trans) != 0)
       {
         break;
@@ -348,20 +354,21 @@ xrdp_listen_main_loop(struct xrdp_listen* self)
       {
         break;
       }
+      timeout = -1;
       /* build the wait obj list */
       robjs_count = 0;
       robjs[robjs_count++] = sync_obj;
       robjs[robjs_count++] = done_obj;
-      /* wait */
-      if (g_obj_wait(robjs, robjs_count, 0, 0, -1) != 0)
+      /* wait - timeout -1 means wait indefinitely*/
+      if (g_obj_wait(robjs, robjs_count, 0, 0, timeout) != 0)
       {
         /* error, should not get here */
         g_sleep(100);
       }
-      if (g_is_wait_obj_set(sync_obj)) /* sync */
+      if (g_is_wait_obj_set(sync_obj)) /* some function must be processed by this thread */
       {
         g_reset_wait_obj(sync_obj);
-        g_loop();
+        g_process_waiting_function(); /* run the function that is waiting*/
       }
       if (g_is_wait_obj_set(done_obj)) /* pro_done_event */
       {
diff --git a/xrdp/xrdp_mm.c b/xrdp/xrdp_mm.c
index 223b128b..2d14351f 100644
--- a/xrdp/xrdp_mm.c
+++ b/xrdp/xrdp_mm.c
@@ -62,6 +62,7 @@ xrdp_mm_sync_load(long param1, long param2)
 static void APP_CC
 xrdp_mm_module_cleanup(struct xrdp_mm* self)
 {
+  g_writeln("xrdp_mm_module_cleanup");
   if (self->mod != 0)
   {
     if (self->mod_exit != 0)
@@ -72,7 +73,7 @@ xrdp_mm_module_cleanup(struct xrdp_mm* self)
   }
   if (self->mod_handle != 0)
   {
-    /* main thread unload */
+    /* Let the main thread unload the module.*/
     g_xrdp_sync(xrdp_mm_sync_unload, self->mod_handle, 0);
   }
   trans_delete(self->chan_trans);
@@ -280,6 +281,7 @@ xrdp_mm_setup_mod1(struct xrdp_mm* self)
   }
   if (self->mod_handle == 0)
   {
+    /* Let the main thread load the lib,*/  
     self->mod_handle = g_xrdp_sync(xrdp_mm_sync_load, (long)lib, 0);
     if (self->mod_handle != 0)
     {
@@ -1084,11 +1086,11 @@ xrdp_mm_get_wait_objs(struct xrdp_mm* self,
   rv = 0;
   if ((self->sesman_trans != 0) && self->sesman_trans_up)
   {
-    trans_get_wait_objs(self->sesman_trans, read_objs, rcount, timeout);
+    trans_get_wait_objs(self->sesman_trans, read_objs, rcount);
   }
   if ((self->chan_trans != 0) && self->chan_trans_up)
   {
-    trans_get_wait_objs(self->chan_trans, read_objs, rcount, timeout);
+    trans_get_wait_objs(self->chan_trans, read_objs, rcount);
   }
   if (self->mod != 0)
   {
diff --git a/xrdp/xrdp_process.c b/xrdp/xrdp_process.c
index df69d057..7a88d524 100644
--- a/xrdp/xrdp_process.c
+++ b/xrdp/xrdp_process.c
@@ -161,7 +161,7 @@ xrdp_process_main_loop(struct xrdp_process* self)
       robjs[robjs_count++] = self->self_term_event;
       xrdp_wm_get_wait_objs(self->wm, robjs, &robjs_count,
                             wobjs, &wobjs_count, &timeout);
-      trans_get_wait_objs(self->server_trans, robjs, &robjs_count, &timeout);
+      trans_get_wait_objs(self->server_trans, robjs, &robjs_count);
       /* wait */
       if (g_obj_wait(robjs, robjs_count, wobjs, wobjs_count, timeout) != 0)
       {
diff --git a/xrdp/xrdpwin.c b/xrdp/xrdpwin.c
index d2c2d0f3..849f7112 100644
--- a/xrdp/xrdpwin.c
+++ b/xrdp/xrdpwin.c
@@ -140,7 +140,7 @@ pipe_sig(int sig_num)
 
 /*****************************************************************************/
 void APP_CC
-g_loop(void)
+g_process_waiting_function(void)
 {
   tc_mutex_lock(g_sync_mutex);
   if (g_sync_command != 0)