Using Macros for Error Handling

OLE 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 provide conversion between the two 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 in order to provide compatibility and make porting easier. Newly written code should use the HRESULT macros and functions.

Error handling macros are listed below. Refer to The OLE Programmer’s Reference for a complete description of each.

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.

RESULT_FROM_WIN32

Maps a Win32 error value into an HRESULT. This assumes that Win32 errors fall in the range -32k to 32k.

HRESULT_FORM_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.