This macro is used to validate parameters passed to a function.
These macros provide a mechanism to detect and notify the user of incorrect parameter usage.
The macro calls ATLASSERT and if the condition fails calls AtlThrow.
In the ATLENSURE case, AtlThrow is called with E_FAIL.
In the ATLENSURE_THROW case, AtlThrow is called with the specified HRESULT.
The difference between ATLENSURE and ATLASSERT is that ATLENSURE throws an exception in Release builds as well as in Debug builds.