LoadString() method doesn't work in C++

Question

I am trying to load a string from my Strin Table in the DLL file I am working on. Here is the function that is supposed to load the string into a std::wstring (since my project uses Unicode charset).

void ErrorHandler::load_error_string()
{
  m_hInst = AfxGetInstanceHandle();
  wchar_t buffer[1024] = { '\0' };
  std::size_t string_length = LoadStringW(this->m_hInst, this->m_error_id, buffer, 1024);

  this->m_raw_content = std::wstring(buffer, string_length);

  CStringW output;
  output.Format(L"%d", m_raw_content.length());

  AfxMessageBox(output);
}

I have created the last three lines for diagnosing the method. The output of AfxMessageBox() is 0.

Where am I wrong?

keep in mind that `string_length` may represent the size of a `std::wstring`, and `std::wstring` has `wchar_t`, which one can be, for instantece 2 bytes. So there is a chance that you must do a `byte conversion`... something like m_raw_content.length()*sizeof(wchar_t), of course depending on your `output.Format` implementation. — wesley.mesquita, Jan 27 '14 at 13:56
the `output` variable is just for diagnosing. I have written that because that method is not working. — Victor, Jan 27 '14 at 14:01
So, Did you check the value of `string_length`? What is the value? — hyun, Jan 27 '14 at 14:13

score 2 · Accepted Answer · edited May 23 '17 at 11:44

2

AfxGetInstanceHandle() gives you the HINSTANCE of the running executable. This means that your LoadStringW call will be looking in the exe's resource table for your string, which will fail, as the strings are in your DLL.

Instead, you'll need to grab the HINSTANCE of the DLL itself - this is provided as the first parameter to DllMain() in your DLL.

See this answer for an example: https://stackoverflow.com/a/2396380/1073843

EDIT: If you're using an MFC DLL, then it's possible you just need to add a call to AFX_MANAGE_STATE(AfxGetStaticModuleState()); at the top of any entry points into your DLL (before AfxGetInstanceHandle() is called.)

edited May 23 '17 at 11:44

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answered Jan 27 '14 at 14:09

benjymous

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I don't have any DLLMain in my project :)) – Victor Jan 27 '14 at 14:10
You should be able to just add one - see the post I linked to – benjymous Jan 27 '14 at 14:11
You could try the second method given in the post I linked to - otherwise, MSDN has the details on what you have to do to override dllmain in your own dll: http://support.microsoft.com/kb/148791 – benjymous Jan 27 '14 at 14:18
Or see my edit to my answer - add `AFX_MANAGE_STATE(AfxGetStaticModuleState());` to your DLL entry points – benjymous Jan 27 '14 at 14:20
AfxGetResourceHandle() ? – user1793036 Jan 28 '14 at 03:15

score 0 · Answer 2 · edited May 23 '17 at 11:44

0

Take a look at this question, which will show you how to get the HINSTANCE of your DLL if it's an MFC DLL.

edited May 23 '17 at 11:44

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answered Jan 27 '14 at 14:15

Sean

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LoadString() method doesn't work in C++

2 Answers2