急....DllMain问题

Question

我做了一个win32的DLL,在DLL中定义了一个全局变量g_hInst=NULL,在DllMain内将DLL的实例hInstance保存到全局变量中g_hInst,  在客户端::LoadLibrary后,发现该g_hInst的值仍为NULL, 何解?

Answer 1

怎么会？看看是不是你什么地方写错了？
检查一下你在DllMain的什么地方赋值的，会不会有问题，其他地方还有没有赋值，装载是否成功等等。

Answer 2

extern "C"
BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
 )
{
g_hInstance = (HINSTANCE)hModule;
    switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
case DLL_THREAD_ATTACH:
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
    }
    return TRUE;
}
在程序结束时,才FreeLibrary的.

Answer 3

应该在DLL_PROCESS_ATTACH时获取,这么写:
HINSTANCE hinst = NULL; HWND hwndDLG = NULL; BOOL CALLBACK DlgProc(HWND hDlg, UINT message,WPARAM wParam, LPARAM lParam);BOOL CALLBACK AboutProc(HWND hDlg, UINT message,WPARAM wParam, LPARAM lParam);extern "C" __declspec(dllexport) void ShowDlg(); BOOL APIENTRY DllMain( HANDLE hModule,                        DWORD  ul_reason_for_call,                        LPVOID lpReserved                                    ){       switch(ul_reason_for_call)       {       case DLL_PROCESS_ATTACH:              hinst = (HINSTANCE)hModule;       case DLL_PROCESS_DETACH:              break;       }    return TRUE;}

Answer 4

switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH: //进程调用LoadLibrary
                      g_hInst = (HINSTANCE)hModule;//在这里保存hinstance
case DLL_THREAD_ATTACH:    //线程调用LoadLibrary
case DLL_THREAD_DETACH:    //线程调用FreeLibrary
case DLL_PROCESS_DETACH:   //进程调用FreeLibrary
break;
    }

Answer 5

把这种要与外界通信的变量写道共享数据段就可以了。
#pragma data_seg("Shared")HINSTANCE g_hIns = NULL;#pragma data_seg()#pragma comment(linker,"/Section:Shared,rws") //设置全局共享数据段的属性