用CreateFile打開串口超過com10就不能打開,解決辦法

10以下的串口可以這樣打開

CreateFile( 
              "COM5",          //  address  of  name  of  the  communications  device 
              fdwAccess,                    //  access  (read-write)  mode 
              0,                                    //  share  mode 
              NULL,                              //  address  of  security  descriptor 
              OPEN_EXISTING,            //  how  to  create 
              0,                                    //  file  attributes 
              NULL                                //  handle  of  file  with  attributes  to  copy 
        ); 

10以上的串口要這樣才打的開

CreateFile( 
              "\\\\.\\COM10",          //  address  of  name  of  the  communications  device 
              fdwAccess,                    //  access  (read-write)  mode 
              0,                                    //  share  mode 
              NULL,                              //  address  of  security  descriptor 
              OPEN_EXISTING,            //  how  to  create 
              0,                                    //  file  attributes 
              NULL                                //  handle  of  file  with  attributes  to  copy 
        );