Call CTRecord.GetFieldLength() to retrieve the field's actual size. For variable length fields such as FIELD_TYPE.VARCHAR and FIELD_TYPE.VARBINARY, the actual size in a record may vary from the defined size.
// check if field 0 actual size is different from defined size
if (ARecord.GetFieldSize(0) != ARecord.GetFieldLength(0))
{
Console.Write("Field 0 defined and actual sizes are different\n");
}