c++ - DLL 中的全局构造函数和 MSVCRT

Question

DLL 中的以下代码会发生什么情况？

#include <vector>
std::vector<int> global_vector;

BOOL WINAPI DllMain(HANDLE hModule, DWORD fdwReason, LPVOID lpReserved)
{
    if (fdwReason == DLL_PROCESS_ATTACH)
    {
        global_vector.push_back(1);
    }

    return TRUE;
}

...如果使用/MD 编译？ vector 的构造函数和 push_back 调用的代码(即内存管理、异常处理...)位于 MSVCRT.DLL... 据我所知，在这个阶段不能保证被映射。它是否得到特殊对待？

Answer 1

来自 here :

In a nutshell, when DllMain is called, OS loader is in a rather fragile state. First off, it has applied a lock on its structures to prevent internal corruption while inside that call, and secondly, some of your dependencies may not be in a fully loaded state. Before a binary gets loaded, OS Loader looks at its static dependencies. If those require additional dependencies, it looks at them as well. As a result of this analysis, it comes up with a sequence in which DllMains of those binaries need to be called. It's pretty smart about things and in most cases you can even get away with not following most of the rules described in MSDN - but not always.