C / C++ / MFC

header file of the application
class CTCCApp : public CWinApp
{
public:
  CTCCApp();
  ...

private:
  int theIntegerVarToBeAccessed;

public:
  int GetTheIntegerValue();
  void SetTheIntegerValue(int iValue);

implementation file of the application
/*---------------------------------------------
COMMENTS FIRST
1. Initialize your variable at the application's constructor or in initinstance...
2. You'll be able to see that somewhere near top the implementation file there's a line like this one:
CTCCApp TCCApp; (You should substitute "TCC" for your text string) This is your app....
---------------------------------------------*/

// Now the functions that you use to access the number...
// SETTING THE VALUE:
void CTCCApp::SetTheIntegerValue(int iValue)
{
  // Process the value and make whatever you want with it before setting it to your integer variable...
  theIntegerVarToBeAccessed = iValue;
}

// GETTING THE VALUE:
int CTCCApp::GetIntegerValue()
{
  return theIntegerVarToBeAccessed;
}

Where you need to access that integer (let's say WHERE.cpp)
/*---------------------------------------------
COMMENTS FIRST
Be sure that you have a #include "TCCApp.h"; in your header or in your implementation file.
---------------------------------------------*/
//Inside the function where you want to access that:
extern CTCCApp TCCApp;
// Now you can get:
TCCApp.GetIntegerValue();
TCCApp.SetIntegerValue(10);

this->AddPage(&this->m_PPDlgParametritzacioDirectaEixos);
this->m_PPDlgParametritzacioDirectaEixos.m_psp.dwFlags |= PSP_USETITLE;
this->m_PPDlgParametritzacioDirectaEixos.m_psp.pszTitle = "Ejes";

ShellExecute ( hwndYourWindow, _T("open"), _T("mailto:user@hostname.com"),
               NULL, NULL, SW_SHOWNORMAL );