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MySQL连接器/c++:GETXDRIVRIVIN()从全局构造调用时崩溃

mysql-connector mysql c++

Atul · 技术社区 · 6 年前

get_driver_instance 从全局对象的c'tor,它只是崩溃抛出异常:访问冲突读取位置。

示例代码:

#define CPPCONN_LIB_BUILD // Need to include this as we are linking mysql connector in static library
#include "MySQL\Src\mysql-connector-c++-1.1.5\cppconn\driver.h"

#pragma comment(lib,"MySQL\\Src\\mysql-connector-c++-1.1.5\\BLD\\driver\\Debug\\mysqlcppconn-static.lib")
#pragma comment(lib,"MySQL\\Src\\mysql-5.6.24\\BLD\\libmysql\\Debug\\mysqlclient.lib")

struct someclass
{
    sql::Driver *m_pDriver;

    someclass()
    {
        /* Create a connection */
        m_pDriver= get_driver_instance(); // It crashes here
        cout << "print something";
    }
} someclass_instance;

int main(int argc, char** argv) 
{
    // We don't need to do anything here. The problem occurs in the global class constructor which executes before main as we've defined its global instance.

    return 0;
}

引发的异常类似于:

Sample.exe中0x000007F6BE17485D处的未处理异常:0xc000005: 访问冲突读取位置0x0000000000000008。

崩溃时的Stacktrace:

Sample.exe!std::_Tree<class std::_Tmap_traits<class sql::SQLString,class boost::shared_ptr<class sql::mysql::MySQL_Driver>,struct std::less<class sql::SQLString>,class std::allocator<struct std::pair<class sql::SQLString const ,class boost::shared_ptr<class sql::mysql::MySQL_Driver> > >,0> >::_Lbound(class sql::SQLString const &) Unknown
Sample.exe!std::_Tree<class std::_Tmap_traits<class sql::SQLString,class boost::shared_ptr<class sql::mysql::MySQL_Driver>,struct std::less<class sql::SQLString>,class std::allocator<struct std::pair<class sql::SQLString const ,class boost::shared_ptr<class sql::mysql::MySQL_Driver> > >,0> >::lower_bound(class sql::SQLString const &) Unknown
Sample.exe!std::_Tree<class std::_Tmap_traits<class sql::SQLString,class boost::shared_ptr<class sql::mysql::MySQL_Driver>,struct std::less<class sql::SQLString>,class std::allocator<struct std::pair<class sql::SQLString const ,class boost::shared_ptr<class sql::mysql::MySQL_Driver> > >,0> >::find(class sql::SQLString const &)    Unknown
Sample.exe!sql::mysql::get_driver_instance_by_name(char const * const)  Unknown
Sample.exe!sql::mysql::get_driver_instance(void)    Unknown
Sample.exe!get_driver_instance()    Unknown
Sample.exe!someclass::someclass() Line 72   C++
Sample.exe!`dynamic initializer for 'obj''() Line 76    C++
Sample.exe!_initterm(void (void) * * pfbegin, void (void) * * pfend) Line 894   C
Sample.exe!_cinit(int initFloatingPrecision) Line 303   C
Sample.exe!__tmainCRTStartup() Line 227 C
Sample.exe!mainCRTStartup() Line 164    C

令人惊讶的是,这种情况只发生在调试版本中。然而,这与 this 问题。 我已确保链接调试生成的连接器库。如果我实例化同一个对象 someclass_instance 但在主函数中它不会崩溃。

注:我花了好几个小时才弄明白。这是真正的问题。在投票前,请至少尝试一次代码。

1 回复 | 直到 6 年前

Alan Birtles 6 年前

您不能依赖于静态初始化不同类的顺序(例如,在您的情况下,调试和发布版本之间的顺序不同)。

这被称为 static initialization order âfiascoâ .

必须避免调用静态初始化程序中的任何代码,该程序本身依赖于静态初始化。

map of names to drivers .

struct someclass
{
    sql::Driver *m_pDriver;

    someclass()
    {
        /* Create a connection */
        m_pDriver= get_driver_instance(); // It crashes here
        cout << "print something";
    }

    void foo() {}
};

someclass& someclass_instance()
{
    static someclass instance;
    return instance;
}

int main(int argc, char** argv) 
{
    someclass_instance().foo();
    return 0;
}

请注意 someclass_instance()

get_driver_instance_by_name (或者提交一个bug报告,让他们为你做这件事)。