How to Use GetCORSystemDirectory()? - c++

Question

HANDLE Proc;
HMODULE hDLL;
hDLL = LoadLibrary(TEXT("mscoree.dll"));
if(hDLL == NULL)
cout << "No Dll with Specified Name" << endl;
else
{
cout << "DLL Handle" << hDLL << endl<<endl;
cout << "Getting the process address..." << endl;
Proc = GetProcAddress(hDLL,"GetRequestedRuntimeVersion");
if(Proc == NULL)
{
FreeLibrary(hDLL);
cout << "Process load FAILED" << endl;
}
else
{
cout << "Process address found at: " << Proc << endl << endl;
LPWSTR st;DWORD* dwlength; ;DWORD cchBuffer=MAX_PATH;
HRESULT hr=GetCORSystemDirectory(st,cchBuffer,dwlength);
if(hr!=NULL)
{
printf("%s",hr);
}
FreeLibrary(hDLL);
}
}
i did like this to get the .NET installation path but i am getting Linker Errors.
error LNK2019: unresolved external symbol _GetCORSystemDirectory#12 referenced in function _main dot.obj

Answer 1

define the GetCORSystemDirectory signature:
typedef HRESULT ( __stdcall *FNPTR_GET_COR_SYS_DIR) ( LPWSTR pbuffer, DWORD cchBuffer, DWORD* dwlength);
initialise the function pointer:
FNPTR_GET_COR_SYS_DIR GetCORSystemDirectory = NULL;
get a function pointer from mscoree.dll and use:
GetCORSystemDirectory = (FNPTR_GET_COR_SYS_DIR) GetProcAddress (hDLL, "GetCORSystemDirectory");
if( GetCORSystemDirectory!=NULL)
{
...
//use GetCORSystemDirectory
...
}
As requested:
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0600
#endif
#include <stdio.h>
#include <tchar.h>
#include <windows.h>
typedef HRESULT (__stdcall *FNPTR_GET_COR_SYS_DIR) ( LPWSTR pbuffer, DWORD cchBuffer, DWORD* dwlength);
FNPTR_GET_COR_SYS_DIR GetCORSystemDirectory = NULL;
int _tmain(int argc, _TCHAR* argv[])
{
HINSTANCE hDLL = LoadLibrary(TEXT("mscoree.dll"));
GetCORSystemDirectory = (FNPTR_GET_COR_SYS_DIR) GetProcAddress (hDLL, "GetCORSystemDirectory");
if( GetCORSystemDirectory!=NULL)
{
TCHAR buffer[MAX_PATH];
DWORD length;
HRESULT hr = GetCORSystemDirectory(buffer,MAX_PATH,&length);
// buffer should contain the folder name
// use it..
}
return 0;
}

Answer 2

You need to pass "GetCORSystemDirectory" as the second parameter into GetProcAddress() - it will return a pointer to that function implementation. Then you'll cast the pointer appropriately and call the function through it.