Detailed introduction to the return value of the hresult Function

Hresult	Value	Description
S_ OK	Zero X 00000000	Successful
S_false	Zero X 00000001	The function is successfully executed, but an error is returned.
E_invalidarg	Zero X 80070057	Parameter Error
E_outofmemory	0x8007000e	Memory application error
E_unexpected	0x8000ffff	Unknown exception
E_notimpl	Zero X 80004001	Features not implemented
E_fail	Zero X 80004005	The error is not described in detail. Obtain the rich error message (note 1)
E_pointer	Zero X 80004003	Invalid Pointer
E_handle	Zero X 80070006	Invalid handle
E_abort	Zero X 80004004	Terminate operation
E_accessdenied	Zero X 80070005	Access denied
E_nointerface	Zero X 80004002	Unsupported Interface

Figure 1 Structure of hresult

Hresult is actually a dubyte value. If the highest bit (BIT) is 0, the result is successful, and 1 indicates an error. For details, see "structure of COM error codes" in msdn. If we need to determine the return value in the program, we can use the comparison operator number, switch statement, or the macro provided by VC:

Hresult hR = call component functions; If (succeeded (HR )){...} // if it succeeds ...... if (failed (HR )){...} // if it fails