Question

我正在尝试实现一个程序，我需要将一个类实例从我的主程序传递到我的共享库函数，用dlsym（）动态打开。

我按如下方式加载我的lib：

IGraphLib*  LibLoader::load(const std::string& file)
{
  this->_dlHandle = dlopen(file.c_str(), RTLD_LAZY);
  if (this->_dlHandle == NULL)
    {
      std::cerr << dlerror() << std::endl;
      return NULL;
    }
  IGraphLib*    (*loadFunc)();

  loadFunc = reinterpret_cast<IGraphLib* (*)()>(dlsym(this->_dlHandle, "load_lib"));
  if (loadFunc == NULL)
    {
      std::cerr << dlerror() << std::endl;
      return NULL;
    }
  IGraphLib*    inst = loadFunc();

  return inst;
}

然后，在我的主程序中，我调用函数'test'，即刚加载的库中类的实例的成员函数。

Nibbler*        game = NULL;

game = new Nibbler(...)
lib = loader->load(av[3]);
lib->test(game);

共享库中的测试函数：

void    NibblerSDL::test(Nibbler* game) const
{
  std::cout << game->getWidth() << std::endl;
}

最后是valgrind错误，它说客户端正在切换堆栈，所以我猜问题会来自这里，我做了一些研究，我尝试用-rdynamic标志进行编译，但是没有改变任何事情：

==5954== Warning: client switching stacks?  SP change: 0x7fefff4c8 --> 0x4ea670a35219e347
==5954==          to suppress, use: --max-stackframe=5667340993508798079 or greater
==5954== Use of uninitialised value of size 8
==5954==    at 0x40172EC: __longjmp (in /lib64/ld-2.18.so)
==5954== 
==5954== Jump to the invalid address stated on the next line
==5954==    at 0x7C9670A35219E1A7: ???
==5954==  Address 0x7c9670a35219e1a7 is not stack'd, malloc'd or (recently) free'd
==5954== 
==5954== Can't extend stack to 0x4ea670a35219d400 during signal delivery for thread 1:
==5954==   no stack segment
==5954== 
==5954== Process terminating with default action of signal 11 (SIGSEGV)
==5954==  Access not within mapped region at address 0x4EA670A35219D400
==5954==    at 0x7C9670A35219E1A7: ???
==5954==  If you believe this happened as a result of a stack
==5954==  overflow in your program's main thread (unlikely but
==5954==  possible), you can try to increase the size of the
==5954==  main thread stack using the --main-stacksize= flag.
==5954==  The main thread stack size used in this run was 8388608.
==5954== Invalid write of size 8
==5954==    at 0x4A22700: _vgnU_freeres (in /usr/lib64/valgrind/vgpreload_core-amd64-linux.so)
==5954==  Address 0x4ea670a35219e2bf is not stack'd, malloc'd or (recently) free'd
==5954== 
==5954== 
==5954== Process terminating with default action of signal 11 (SIGSEGV)
==5954==  General Protection Fault
==5954==    at 0x4A22700: _vgnU_freeres (in /usr/lib64/valgrind/vgpreload_core-amd64-linux.so)
==5954==

库的load_lib函数：

extern "C" IGraphLib*   load_lib()
{
  return new NibblerSDL();
}

C ++将类实例传递给dlsym（）共享库指针

0 个答案: