加载DLL不初始化静态C ++类 [英] Loading DLL not initializing static C++ classes

问题描述

我有一个在运行时加载的DLL。该DLL依赖于一个静态变量用于内部工作（它是一个std :: map），这个变量在DLL中定义。

I have a DLL that is being loaded at run-time. The DLL relies on a static variable for internal workings (it is a std::map), this variable is defined within the DLL.

当我调用第一个函数DLL加载后，我从DLL中得到一个SegFault，映射从未初始化。从我从DLL载入中读取的一切，静态和全局数据初始化应该发生在甚至调用DLLMain之前。

When I call the first function from the DLL after loading, I get a SegFault from the DLL, the map was never initialized. From everything I have read from DLL Loading, static and global data initialization should happen before even the call to DLLMain.

为了测试静态初始化，我添加了一个静态结构打印出来

To test static initialization I added a static struct that prints out a message, and even threw in a breakpoint for good measure.

static struct a
{
  a(void) { puts("Constructing\n"); }
}statica;

没有消息，或在DLLMain或函数调用之前断开。

There was no message, or break before DLLMain or the function is called.

这是我的加载代码：

  dll = LoadLibrary("NetSim");
  //Error Handling

  ChangeReliability   = reinterpret_cast<NetSim::ChangeReliability>
                        (GetProcAddress(dll, "ChangeReliability"));


ChangeReliability(100);

我已经验证了dll版本是正确的，重建整个项目多次，区别。

I have verified that the dll version is the correct one, rebuilt the entire project multiple times, but no difference. I am fresh out of ideas.

推荐答案

链接DLL时，是否指定了ENTRY开关？如果是这样，它将覆盖链接器的默认值，即DllMainCRTStartup。因此，不会调用_CRT_INIT，反过来，将不会调用全局初始化器，这将导致未初始化的全局（静态）数据。

When you linked your DLL, was the /ENTRY switch specified? If so, it'll override the linker's default which is DllMainCRTStartup. As a result, _CRT_INIT won't be called and, in turn, the global initializers won't be called which will result in uninitialized global (static) data.

如果你要为自己的入口点指定/ ENTRY，在进程附加和进程分离期间需要调用_CRT_INIT。

If you are specifying /ENTRY for your own entry point, you need to call _CRT_INIT during process attach and process detach.

如果不指定/ ENTRY，使用CRT的进入点，调用_CRT_INIT在进程连接/分离后调用你的DllMain。

If you are not specifying /ENTRY, the linker should be using the CRT's entry point which calls _CRT_INIT on process attach/detach before calling into your DllMain.

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