V545. Such conditional expression of 'if' operator is incorrect for the HRESULT type value 'Foo'. The SUCCEEDED or FAILED macro should be used instead

27.11.2010

The analyzer detected a potential error related to handling a variable of the HRESULT type.

HRESULT is a 32-bit value divided into three different fields: severity code, device code and error code. Such special constants as S_OK, E_FAIL, E_ABORT, etc. serve to handle HRESULT-values while the SUCCEEDED and FAILED macros are used to check HRESULT-values.

The V545 warning is generated if a variable of the HRESULT type is used in the 'if' operator as a bool-variable. Consider this sample:

HRESULT hr;
...
if (hr)
{
}

'HRESULT' and 'bool' are two types absolutely different in meaning. This sample of comparison is incorrect. The HRESULT type can have many states including 0L (S_OK), 0x80000002L (Ran out of memory), 0x80004005L (unspecified failure) and so on. Note that the code of the state S_OK is 0.

To check the HRESULT-value, we must use macro SUCCEEDED or FAILED defined in "WinError.h". These are correct versions of code:

if (FAILED(hr))
{
}
if (SUCCEEDED(hr))
{
}

References:

You can look at examples of errors from real projects which were detected by this diagnostic message.