COM defines a number of macros that make it easier to work with SCODEs on 16-bit platforms and HRESULTs on both platforms. Some of the macros and functions below convert return values of different data types and are quite useful in code that runs only on 16-bit platforms, code that runs on both 16-bit and 32-bit platforms, and 16-bit code that is being ported to a 32-bit platform. These same macros are meaningless in 32-bit environments and are available to provide compatibility and make porting easier. Newly written code should use the HRESULT macros and functions.
The error handling macros are listed below:
| Macro | Description |
|---|---|
| GetScode | (Obsolete) Returns an SCODE given an HRESULT. |
| ResultFromScode | (Obsolete) Returns an HRESULT given an SCODE. |
| PropagateResult | (Obsolete) Generates an HRESULT to return to a function in cases where an error is being returned from an internally called function. |
| MAKE_HRESULT | Returns an HRESULT given an SCODE that represents an error. |
| MAKE_SCODE | Returns an SCODE given an HRESULT. |
| HRESULT_CODE | Extracts the error code part of the HRESULT. |
| HRESULT_FACILITY | Extracts the facility from the HRESULT. |
| HRESULT_SEVERITY | Extracts the severity bit from the SEVERITY. |
| SCODE_CODE | Extracts the error code part of the SCODE. |
| SCODE_FACILITY | Extracts the facility from the SCODE. |
| SCODE_SEVERITY | Extracts the severity field from the SCODE. |
| SUCCEEDED | Tests the severity of the SCODE or HRESULT - returns TRUE if the severity is zero and FALSE if it is one. |
| FAILED | Tests the severity of the SCODE or HRESULT - returns TRUE if the severity is one and FALSE if it is zero. |
| IS_ERROR | Provides a generic test for errors on any status value. |
| FACILITY_NT_BIT | Defines bits so macros are guaranteed to work. |
| HRESULT_FROM_WIN32 | Maps a Win32 error value into an HRESULT. This assumes that Win32 errors fall in the range -32K to 32K. |
| HRESULT_FROM_NT | Maps an NT status value into an HRESULT. |
Note Calling MAKE_HRESULT for S_OK verification carries a performance penalty. You should not routinely use MAKE_HRESULT for successful results.