C++'da GetOpenFileNameA Hatası alıyorum.

#include<commdlg.h>
#include<string>

std::string OpenFile(const char* filter, GLFWwindow* window){
    OPENFILENAME ofn;
    char szFile[260];
    ZeroMemory(&ofn, sizeof(OPENFILENAME));
    ofn.lStructSize = sizeof(OPENFILENAME);
    ofn.hwndOwner = glfwGetWin32Window(window);
    ofn.lpstrFile = szFile;
    ofn.lpstrFile[0] = '\0';
    ofn.nMaxFile = sizeof(szFile);
    ofn.lpstrFilter = filter;
    ofn.nFilterIndex = 1;
    ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST | OFN_NOCHANGEDIR;

     if(GetOpenFileName(&ofn))
          return ofn.lpstrFile;
      return std::string();
 }