variable 'symbol' not used vnpy_server.mq5 285 11
implicit conversion from 'int' to 'string' vnpy_server.mq5 394 21
implicit conversion from 'ulong' to 'string' vnpy_server.mq5 418 23
implicit conversion from 'string' to 'number' vnpy_server.mq5 419 19
return value of 'OrderSelect' should be checked vnpy_server.mq5 419 7
4 errors, 9 warnings 5 10
variable 'symbol' not used vnpy_server.mq5 285 11 implicit conversion from 'int' to 'string' vnpy_server.mq5 394 21 implicit conversion from 'ulong' to 'string' vnpy_server.mq5 418 23 implicit conversion from 'string' to 'number' vnpy_server.mq5 419 19 return value of 'OrderSelect' should be checked vnpy_server.mq5 419 7 4 errors, 9 warnings 5 10
请问这是什么原因