swift - 在 SQLITE swift 中处理不透明指针

Question

嗨，我是 swift 新手，正在尝试为我的关卡编码项目添加数据库。我似乎无法让不透明的指针在没有错误的情况下正常工作。我使用过教程并且总是遇到同样的错误。我得到的错误：

Expected member name or constructor call after type name on line 3

Cannot convert value of type 'UnsafeMutablePointer<OpaquePointer?.Type>' to expected argument type 'UnsafeMutablePointer<OpaquePointer?>' On line 9

Cannot convert return expression of type 'OpaquePointer?.Type' to return type 'OpaquePointer?' On line 12

    var dbURL = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
    
    func createDatabase() -> OpaquePointer?{
        var db = OpaquePointer?
        let url = NSURL(fileURLWithPath: dbURL)
        
        if let pathComponent = url.appendingPathComponent("Database.sqlite"){
            let filePath = pathComponent.path
            if sqlite3_open(filePath, &db) == SQLITE_OK{
                print("successfully opened database")
                
                return db
            }
          
        }
        
    }

Answer 1

更改var db = OpaquePointer?为var db : OpaquePointer?

添加return nil到函数的末尾。

Answer 2

您需要在第 3 行使用冒号而不是等号。