compile warnings

~/mariadb-10.2/libmariadb$ git log

commit 10d3269e22a36c3f4698723a9b03bc9a9aa235d2

/home/danielgb/mariadb-10.2/libmariadb/plugins/connection/aurora.c: In function ‘aurora_command’:

/home/danielgb/mariadb-10.2/libmariadb/plugins/connection/aurora.c:761:9: warning: this statement may fall through [-Wimplicit-fallthrough=]

         aurora_switch_connection(mysql, aurora, AURORA_PRIMARY);

         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/plugins/connection/aurora.c:764:5: note: here

     default:

     ^~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/plugins/auth/gssapi_client.c: In function ‘auth_client’:

/home/danielgb/mariadb-10.2/libmariadb/plugins/auth/gssapi_client.c:79:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]

   gss_buffer_desc input= {0,0};

   ^~~~~~~~~~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/plugins/auth/gssapi_client.c:57:45: warning: unused parameter ‘mech’ [-Wunused-parameter]

 int auth_client(char *principal_name, char *mech, MYSQL *mysql, MYSQL_PLUGIN_VIO *vio)

                                             ^~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_pvio.c: In function ‘ma_pvio_read’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_pvio.c:264:10: warning: ‘r’ may be used uninitialized in this function [-Wmaybe-uninitialized]

   return r;

          ^

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_pvio.c: In function ‘ma_pvio_write’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_pvio.c:341:11: warning: ‘r’ may be used uninitialized in this function [-Wmaybe-uninitialized]

   ssize_t r;

           ^

/home/danielgb/mariadb-10.2/libmariadb/plugins/pvio/pvio_socket.c: In function ‘pvio_socket_connect’:

/home/danielgb/mariadb-10.2/libmariadb/plugins/pvio/pvio_socket.c:759:42: warning: comparison is always false due to limited range of data type [-Wtype-limits]

     if (pvio_socket_blocking(pvio, 1, 0) == SOCKET_ERROR)

                                          ^~

/home/danielgb/mariadb-10.2/libmariadb/plugins/pvio/pvio_socket.c:871:46: warning: comparison is always false due to limited range of data type [-Wtype-limits]

         if (pvio_socket_blocking(pvio, 0, 0) == SOCKET_ERROR)

                                              ^~

/home/danielgb/mariadb-10.2/libmariadb/plugins/pvio/pvio_socket.c:903:42: warning: comparison is always false due to limited range of data type [-Wtype-limits]

     if (pvio_socket_blocking(pvio, 1, 0) == SOCKET_ERROR)

                                          ^~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_hash.c: In function ‘hash_insert’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_hash.c:383:18: warning: ‘gpos2’ may be used uninitialized in this function [-Wmaybe-uninitialized]

       gpos2->next=NO_RECORD;

       ~~~~~~~~~~~^~~~~~~~~~~ 

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_hash.c:378:17: warning: ‘gpos’ may be used uninitialized in this function [-Wmaybe-uninitialized]

       gpos->next=NO_RECORD;

       ~~~~~~~~~~^~~~~~~~~~~ 

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_hash.c:382:18: warning: ‘ptr_to_rec2’ may be used uninitialized in this function [-Wmaybe-uninitialized]

       gpos2->data=ptr_to_rec2;

       ~~~~~~~~~~~^~~~~~~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_hash.c:377:17: warning: ‘ptr_to_rec’ may be used uninitialized in this function [-Wmaybe-uninitialized]

       gpos->data=ptr_to_rec;

       ~~~~~~~~~~^~~~~~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_dyncol.c: In function ‘mariadb_dyncol_val_double’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_dyncol.c:4044:7: warning: this statement may fall through [-Wimplicit-fallthrough=]

       {

       ^

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_dyncol.c:4060:5: note: here

     case DYN_COL_DATETIME:

     ^~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_dyncol.c:4050:15: warning: argument 1 null where non-null expected [-Wnonnull]

         *dbl= strtod(str, &end);

               ^~~~~~~~~~~~~~~~~

In file included from /home/danielgb/mariadb-10.2/libmariadb/include/ma_global.h:168:0,

                 from /home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_dyncol.c:64:

/usr/include/stdlib.h:164:15: note: in a call to function ‘strtod’ declared here

 extern double strtod (const char *__restrict __nptr,

               ^~~~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_lib.c: In function ‘mariadb_get_infov’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_lib.c:3821:30: warning: this statement may fall through [-Wimplicit-fallthrough=]

       *((unsigned long *)arg)= mysql->client_flag;

       ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_lib.c:3824:3: note: here

   default:

   ^~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_stmt.c: In function ‘store_param’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_stmt.c:607:19: warning: comparison is always false due to limited range of data type [-Wtype-limits]

     if (indicator == STMT_INDICATOR_NTS)

                   ^~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_stmt.c: In function ‘mysql_stmt_execute_generate_request’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/mariadb_stmt.c:798:27: warning: comparison is always false due to limited range of data type [-Wtype-limits]

             if (indicator == STMT_INDICATOR_NTS ||

                           ^~

/home/danielgb/build-mariadb-10.2-gcc7/libmariadb/libmariadb/ma_client_plugin.c: In function ‘mysql_client_register_plugin’:

/home/danielgb/build-mariadb-10.2-gcc7/libmariadb/libmariadb/ma_client_plugin.c:357:11: warning: ‘unused’ may be used uninitialized in this function [-Wmaybe-uninitialized]

     plugin= add_plugin(mysql, plugin, 0, 0, unused);

     ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

/home/danielgb/build-mariadb-10.2-gcc7/libmariadb/libmariadb/ma_client_plugin.c:340:11: note: ‘unused’ was declared here

   va_list unused;

           ^~~~~~

/home/danielgb/build-mariadb-10.2-gcc7/libmariadb/libmariadb/ma_client_plugin.c: In function ‘mysql_client_plugin_init’:

/home/danielgb/build-mariadb-10.2-gcc7/libmariadb/libmariadb/ma_client_plugin.c:190:23: warning: ‘unused’ may be used uninitialized in this function [-Wmaybe-uninitialized]

   if (plugin->init && plugin->init(errbuf, sizeof(errbuf), argc, args))

                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

/home/danielgb/build-mariadb-10.2-gcc7/libmariadb/libmariadb/ma_client_plugin.c:277:11: note: ‘unused’ was declared here

   va_list unused;

           ^~~~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_dtoa.c: In function ‘dtoa’:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_dtoa.c:1465:14: warning: this statement may fall through [-Wimplicit-fallthrough=]

     leftright= 0;

     ~~~~~~~~~^~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_dtoa.c:1467:3: note: here

   case 4:

   ^~~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_dtoa.c:1473:14: warning: this statement may fall through [-Wimplicit-fallthrough=]

     leftright= 0;

     ~~~~~~~~~^~~

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_dtoa.c:1475:3: note: here

   case 5:

   ^~~~

At top level:

/home/danielgb/mariadb-10.2/libmariadb/libmariadb/ma_dtoa.c:1161:21: warning: ‘tinytens’ defined but not used [-Wunused-const-variable=]

 static const double tinytens[]=

                     ^~~~~~~~

/home/danielgb/mariadb-10.2/libmariadb/unittest/libmariadb/t_aurora.c: In function ‘test_reconnect’:

/home/danielgb/mariadb-10.2/libmariadb/unittest/libmariadb/t_aurora.c:100:3: warning: ignoring return value of ‘system’, declared with attribute warn_unused_result [-Wunused-result]

   system("/usr/local/aws/bin/aws rds failover-db-cluster --db-cluster-identifier instance-1-cluster");

   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~