//------------------------------------------------------------------------------------------
//
// Fonction renvoyant true si XG_AppName est installé
// XG_AppName = Nom de l'application ŕ vérifier
//
//------------------------------------------------------------------------------------------

#define MAX_KEY_LENGTH 255
#define MAX_VALUE_NAME 16383


BOOLEAN QueryKey(HKEY hKey, wchar_t* XG_AppName) 
{ 
    TCHAR    achKey[MAX_KEY_LENGTH];   // buffer for subkey name
    DWORD    cbName;                   // size of name string 
    TCHAR    achClass[MAX_PATH] = TEXT("");  // buffer for class name 
    DWORD    cchClassName = MAX_PATH;  // size of class string 
    DWORD    cSubKeys=0;               // number of subkeys 
    DWORD    cbMaxSubKey;              // longest subkey size 
    DWORD    cchMaxClass;              // longest class string 
    DWORD    cValues;              // number of values for key 
    DWORD    cchMaxValue;          // longest value name 
    DWORD    cbMaxValueData;       // longest value data 
    DWORD    cbSecurityDescriptor; // size of security descriptor 
    FILETIME ftLastWriteTime;      // last write time 

	DWORD i, retCode; 
  
    // Get the class name and the value count. 
    retCode = RegQueryInfoKey(
        hKey,                    // key handle 
        achClass,                // buffer for class name 
        &cchClassName,           // size of class string 
        NULL,                    // reserved 
        &cSubKeys,               // number of subkeys 
        &cbMaxSubKey,            // longest subkey size 
        &cchMaxClass,            // longest class string 
        &cValues,                // number of values for this key 
        &cchMaxValue,            // longest value name 
        &cbMaxValueData,         // longest value data 
        &cbSecurityDescriptor,   // security descriptor 
        &ftLastWriteTime);       // last write time 
 
    // Enumerate the subkeys, until RegEnumKeyEx fails.
   
    if (cSubKeys)
    {
        for (i=0; i<cSubKeys; i++) 
        { 
            cbName = MAX_KEY_LENGTH;
            retCode = RegEnumKeyEx(hKey, i,
                     achKey, 
                     &cbName, 
                     NULL, 
                     NULL, 
                     NULL, 
                     &ftLastWriteTime); 
            if (retCode == ERROR_SUCCESS) 
            {				
				if(_tcscmp(achKey, XG_AppName)==0)
				{
					return true;			
				}
            }
        }
    }
	return false;
}