完成语句时SQLite发生奇怪的崩溃

我用SQLite编写了一个C++测试应用程序,我做了一个小包装器。

一件奇怪的事情:我现在显示返回的语句指针(通过printf(“%p”)),第一次读取时它总是0048D228。撞车的是666767。

以下是我课程的重要部分:

class SQLiteResultSet
{
private:
    sqlite3_stmt *stmt;
public:
    inline SQLiteResultSet(sqlite3_stmt *pStmt) : stmt(pStmt) {}
    inline bool next() { return sqlite3_step(stmt) == SQLITE_ROW; }
    inline const unsigned char *textColumn(int colNum) { 
        return sqlite3_column_text(stmt, colNum); 
    }
    inline const int intColumn(int colNum) {
        return sqlite3_column_int(stmt, colNum); 
    }
    inline void close() { 
        if(isOpen()) { 
            printf("----closing %p\n",stmt);
            sqlite3_finalize(stmt); 
            printf("----closed\n");
            stmt = NULL; 
        } 
    }
    inline bool isOpen() { return stmt != NULL; }
    inline ~SQLiteResultSet() { close(); }
};

class SQLiteGateway
{
private:
    sqlite3 *db;
    SQLiteResultSet *rs;

    void resetResultSet();

public:
    SQLiteGateway(char *dbName);
    SQLiteResultSet *select(char *query);
    bool tableExists(char *tableName);
    void execute(char *query);
public:
    ~SQLiteGateway(void);
};

SQLiteGateway::SQLiteGateway(char *dbName)
{
    db = NULL;
    rs = NULL;
    int error = sqlite3_open(dbName, &db);
    if (error)
    {
        throw sqlite3_errmsg(db);
    }
}

void SQLiteGateway::resetResultSet()
{
    if(rs != NULL)
    {
        delete rs;
        rs = NULL;
    }
}

SQLiteResultSet *SQLiteGateway::select(char *query)
{
    sqlite3_stmt    *res;
    const char      *tail;

    resetResultSet();

    int error = sqlite3_prepare_v2(db,query,-1,&res,&tail);
    if (error != SQLITE_OK || res == NULL)
    {
        throw sqlite3_errmsg(db);
    }

    rs = new SQLiteResultSet(res);
    return rs;
}

SQLiteGateway::~SQLiteGateway(void)
{
    resetResultSet();

    if(db != NULL)
    {
        sqlite3_close (db); 
    }
}

编辑:测试程序!

注意:从SQLiteGateway的声明中删除tableExists()和execute(),我没有在这里复制它们的主体,它们也没有在这个测试中使用。

int main()
{
    SQLiteGateway *sqlg = NULL;
    try
    {
        sqlg = new SQLiteGateway("./apptest.db");

        for(int i=0; i<5; i++)
        {
            SQLiteResultSet *rs = sqlg->select("select x from mytable");
            if(rs->next()) printf("%d\n", rs->intColumn(0));
            delete rs;
        }
    }
    catch(char *str)
    {
        printf("Abnormal termination: %s\n", str);
    }
    if(sqlg != NULL) 
    {
        delete sqlg;
    }
}

0
----closing 0048D1E0
----closed
0
----closing 0048D1E0
----closed
----closing 0048DFF8