| Previous | Next |
| STG_E_UNKNOWN | STG_E_INVALIDFLAG |
STG_E_UNIMPLEMENTEDFUNCTION
Structured-storage function is not implemented
STG_E_UNIMPLEMENTEDFUNCTION is HRESULT 2147680510 (0x800300FE) from winerror.h. The documented description is “That function is not implemented.” The result belongs to an optional or version-dependent method on a storage provider. A reliable diagnosis preserves the raw value and reconstructs the state that made this true: the object exposes the interface but its implementation does not provide the requested function.
STG_E_UNIMPLEMENTEDFUNCTION means that the object exposes the interface but its implementation does not provide the requested function.
Where the result appears
- This result can surface in a IStorage, IStream, ILockBytes, property storage, compound-file parsing, or persistence code.
- Map the failure to one concrete operation among StgOpenStorage, StgCreateStorageEx, IStorage, IStream, IPropertyStorage, STATSTG, and the selected STGM mode.
- Preserve storage path or identity, STGM mode, stream or storage name, transaction generation, file hash, and backing provider before releasing or replacing the object that returned this result.
An incident record must distinguish caller, runtime, provider, and backing resource while testing whether the object exposes the interface but its implementation does not provide the requested function.
Typical causes and interpretation
The immediate contract boundary is specific: the object exposes the interface but its implementation does not provide the requested function. Common cause branches include the following:
- A lightweight provider implements only a subset of IStorage.
- The operating-system or component version predates the function.
- A proxy advertises an interface more broadly than its backend supports.
Confirm the cause branch that explains why the object exposes the interface but its implementation does not provide the requested function by using call arguments, object state, metadata, device information, or provider traces.
Correct handling and recovery
The primary recovery is to use the documented fallback or capability test and do not repeat the unsupported call unchanged. The failure report should capture the relevant state during an optional or version-dependent method on a storage provider so it is clear why the object exposes the interface but its implementation does not provide the requested function.
When it follows cancellation or replacement, create a new generation before applying the recovery: use the documented fallback or capability test and do not repeat the unsupported call unchanged.
Practical scenario
A virtual storage provider accepts stream reads but does not implement transactional commit, so the client switches to export-and-replace.
Difference from related HRESULTs
STG_E_INVALIDFUNCTION can mean the operation is inappropriate in the current context; it specifically says the implementation lacks it.
Developer and administrator guidance
A runbook should preserve the original artifact and logs before the proposed recovery—use the documented fallback or capability test and do not repeat the unsupported call unchanged—changes evidence.
References
Looking for a different code? Search another status or error code.