C6215

warning C6215: cast between semantically different integer types: a Boolean type to HRESULT

This warning indicates that a Boolean is being cast to an HRESULT. Boolean types indicate success by a non-zero value, whereas success (S_OK) in HRESULT is indicated by a value of 0. Casting a Boolean type to an HRESULT and then using it in a test expression will yield an incorrect result.

This warning frequently occurs when a Boolean is used as an argument to SUCCEEDED or FAILED macro, which explicitly casts their arguments to an HRESULT.

Example

The following code generates this warning:

#include <windows.h>
BOOL IsEqual(REFGUID, REFGUID);

void f( REFGUID riid1, REFGUID riid2 )
{
  if (SUCCEEDED( IsEqual( riid1, riid2 ) )) //warning 6215
  {
    // success code ...
  }
  else
  {
    // failure code ...
  }
}

Generally, the SUCCEEDED or FAILED macros should only be applied to HRESULT.

To correct this warning, use the following code:

#include <windows.h>
BOOL IsEqual(REFGUID, REFGUID);

void f( REFGUID riid1, REFGUID riid2 )
{
  if (IsEqual( riid1, riid2 ) == TRUE) 
  {
    // code for riid1 == riid2
  }
  else
  {
    // code for riid1 != riid2
  }
}

For more information, see SUCCEEDED Macro and FAILED Macro