Question

I’m looking for something equivalent to the following macro:

#define FAILED_CHECK(hr) if(FAILED(hr)) return hr;

is there any implementation inside the ATL library that does as shown above?

thanks!

Answer 1

For whatever reason, ATL have not been providing an extremely useful macro like requested. Starting a few releases of Visual Studio back, ATL introduced similar macros:

/* Naming is slightly off in these macros
ATLENSURE_RETURN(condition) is an HRESULT return of E_FAIL
ATLENSURE_RETURN_VAL(condition, hr) is any return value (function can pick)
ATLENSURE_RETURN_HR(condition, hr) is HRESULT-specific, though currently the same as _VAL
*/

but once again, there was no immediate match. You have to define your own. Or alternatively, switch to throwing exceptions on error conditions. ATL provides useful macros for this: ATLENSURE_THROW, ATLENSURE_SUCCEEDED and friends.

In particular, you can throw exception on failure HRESULT using ATLENSURE_SUCCEEDED and then catch exception, esp. before return from COM interface call, converting it back to HRESULT:

_ATLTRY {
  // ...
  ATLENSURE_SUCCEEDED(pFoo->Bar()); // Bar returns HRESULT 
  // ...
} _ATLCATCH(Exception) { // CAtlException class
  return Exception; // Back to HRESULT through CAtlException's operator
}