Standard COM Errors
Many, but not all, of the properties and methods of the Commerce Server objects use standard Component Object Model (COM) HRESULT return values to communicate whether the operation was successful or not.
In C++, these values are the actual return values from the methods themselves (including property get_ and put_ methods). The program must explicitly perform error checking by examining these return values, or use some variation of structured error handling.
In Microsoft Visual Basic (VB), and in Visual Basic Scripting Edition (VBS) as used in Active Server Pages (ASP), these values are placed in the Number property of the global Err object. Error handling is either handled automatically, displaying a standard error dialog box, or explicitly by the program, checking the value of the Number property of the global Err object. The On Error Resume Next command disables automatic error handling, thereby enabling explicit error handling.
The following table shows the most common standard COM errors returned by the properties and methods of the Commerce Server objects.
| Constant | Value (32-bit) | Description |
| S_OK | 00000000 | The standard return value used to communicate successful completion. |
| S_FALSE | 00000001 | An alternate success value, typically used to communicate successful, but non-standard completion. The precise meaning depends on the method or property in question. |
| E_UNEXPECTED | 8000FFFF | Catastrophic failure error. |
| E_NOTIMPL | 80004001 | Not implemented error. |
| E_OUTOFMEMORY | 8007000E | Out of memory error. |
| E_INVALIDARG | 80070057 | One or more arguments are not valid error. |
| E_NOINTERFACE | 80004002 | Interface not supported error. |
| E_POINTER | 80004003 | Pointer not valid error. |
| E_HANDLE | 80070006 | Handle not valid error. |
| E_ABORT | 80004004 | Operation aborted error. |
| E_FAIL | 80004005 | Unspecified error. |
| E_ACCESSDENIED | 80070005 | General access denied error. |
Additional information may be available using the global Err object. In Visual Basic, the Description property of the Err object may contain a text description of the error.
In C++, call the API function GetErrorInfo to retrieve the most recently set IErrorInfo pointer in the current logical thread. The GetDescription method of that interface may return a text description of the error.