Proposed fix for bug #3412 (embedded server: prepared statement returns

empty recordset where some records should be found)

sql/ha_myisam.cc

@@ -60,13 +60,11 @@ static void mi_check_print_msg(MI_CHECK *param,	const char* msg_type,
 
   DBUG_PRINT(msg_type,("message: %s",msgbuf));
 
-#ifndef EMBEDDED_LIBRARY
-  if (thd->net.vio == 0)
+  if (!thd->vio_ok())
   {
     sql_print_error(msgbuf);
     return;
   }
-#endif
 
   if (param->testflag & (T_CREATE_MISSING_KEYS | T_SAFE_REPAIR |
 			 T_AUTO_REPAIR))

sql/mysqld.cc

@@ -661,7 +661,7 @@ static void close_connections(void)
       break;
     }
 #ifndef __bsdi__				// Bug in BSDI kernel
-    if (tmp->net.vio)
+    if (tmp->vio_ok())
     {
       sql_print_error(ER(ER_FORCING_CLOSE),my_progname,
 		      tmp->thread_id,tmp->user ? tmp->user : "");

sql/slave.cc

@@ -1386,7 +1386,7 @@ int fetch_master_table(THD *thd, const char *db_name, const char *table_name,
   thd->net.no_send_ok = 0; // Clear up garbage after create_table_from_dump
   if (!called_connected)
     mysql_close(mysql);
-  if (errmsg && thd->net.vio)
+  if (errmsg && thd->vio_ok())
     send_error(thd, error, errmsg);
   DBUG_RETURN(test(error));			// Return 1 on error
 }

sql/sql_class.cc

@@ -746,7 +746,7 @@ bool select_send::send_data(List<Item> &items)
     }
   }
   thd->sent_row_count++;
-  if (!thd->net.vio)
+  if (!thd->vio_ok())
     DBUG_RETURN(0);
   if (!thd->net.report_error)
     DBUG_RETURN(protocol->write());

sql/sql_class.h

@@ -932,8 +932,10 @@ class THD :public ilink,
     net.last_errno= 0;
     net.report_error= 0;
   }
+  inline bool vio_ok() const { return net.vio; }
 #else
   void clear_error();
+  inline bool vio_ok() const { return true; }
 #endif
   inline void fatal_error()
   {

sql/sql_show.cc

@@ -1540,13 +1540,8 @@ void mysqld_list_processes(THD *thd,const char *user, bool verbose)
     while ((tmp=it++))
     {
       struct st_my_thread_var *mysys_var;
-#ifndef EMBEDDED_LIBRARY
-      if ((tmp->net.vio || tmp->system_thread) &&
-          (!user || (tmp->user && !strcmp(tmp->user,user))))
-#else
-      if (tmp->system_thread &&
+      if ((tmp->vio_ok() || tmp->system_thread) &&
           (!user || (tmp->user && !strcmp(tmp->user,user))))
-#endif
       {
         thread_info *thd_info=new thread_info;