Errors | UForm for Mojo

Every fallible entry point raises Error and nothing else, since Mojo allows one error type per function. An Error carries a Status shared with the C interface, so a fault this binding catches before the boundary reports the status the engine would have reported for the same fault:

try:
    _ = Model.load_ram(executor, "missing.safetensors")
except error:
    if error.status == Status.IO:
        pass
    print(error)  # UForm: io [uform_model_load_ram]: ...

An Error keeps the engine mapped while it lives, since its name and message are the engine’s own static text.

API

StructStatusWhy a call into the engine failed, the uform_status_t vocabulary verbatim.1

struct Status

An Error never carries SUCCESS or DEFERRED: only a Deferred reports the latter, and only until its call is final. Library.status_name spells each one as the engine does.

Fields

`code`	`Int32`	The raw `uform_status_t` value, kept even when this build does not name it.

Values

`SUCCESS`	`Status(Int32(0))`	The call completed.
`DEFERRED`	`Status(Int32(1))`	The call was submitted deferred and is not final yet; the one non-final status.
`OUT_OF_MEMORY`	`Status(Int32(2))`	Device, pinned or host memory could not be allocated, or the scratch ceiling is too low.
`SHAPE_MISMATCH`	`Status(Int32(3))`	Item counts, a pixel shape, or a batch envelope disagree with the call or the model.
`UNSUPPORTED_LAYOUT`	`Status(Int32(4))`	A stride or packing the model cannot read.
`UNKNOWN_KIND`	`Status(Int32(5))`	A scalar, modality or name this build does not know.
`IO`	`Status(Int32(7))`	A checkpoint file could not be opened, read or written.
`DEVICE`	`Status(Int32(8))`	The driver refused or the device faulted; after a fault the executor refuses every later call.
`MALFORMED`	`Status(Int32(9))`	Supplied bytes could not be decoded: a checkpoint, an image, a clip or a recording.
`INTERNAL`	`Status(Int32(10))`	The library reported neither success nor a failure, which names a defect rather than a state.
`CONFIG_MISMATCH`	`Status(Int32(13))`	The request contradicts a frozen configuration, like resuming a checkpoint of another geometry.
`CONTENDED`	`Status(Int32(14))`	The call was refused rather than waited for, like a submission to a full deferred table.
`CANCELLED`	`Status(Int32(15))`	A progress handler asked the call to stop; it unwound and published nothing.
`UNSUPPORTED`	`Status(Int32(16))`	The verb is declared for every residency or model, but this one does not implement it.
`INVALID_ARGUMENT`	`Status(Int32(17))`	An argument breaks the verb's contract, like a read of a result whose arena a later call rewound.
`LIBRARY_MISSING`	`Status(Int32(-1))`	Nothing to `dlopen`, the binding's own.
`SYMBOL_MISSING`	`Status(Int32(-2))`	The library loaded but does not export a symbol the binding needs, the binding's own.
`VERSION_MISMATCH`	`Status(Int32(-3))`	The library loaded but reports a different major version than the binding's, the binding's own.

Conforms to

Copyable, Deinitable, Equatable, ImplicitlyCopyable, Movable, RegisterPassable, TrivialRegisterPassable

ofLifts a raw uform_status_t, keeping an unnamed one rather than guessing.

def of(code: Int32) -> Self

StructErrorWhat went wrong inside the engine, and which entry point it was about.2

struct Error

Fields

`status`	`Status`	Which class of failure the engine reported.
`detail`	`StaticString`	The entry point it was about, for a reader rather than for a branch.
`message`	`Optional[Pointer[Scalar[_c_char_dtype()], ImmUntrackedOrigin]]`	The engine's own static message, which outlives the call and needs no freeing.
`name`	`Optional[Pointer[Scalar[_c_char_dtype()], ImmUntrackedOrigin]]`	The engine's spelling of `status`, absent where no engine named it.
`library`	`Optional[Library]`	The engine `message` and `name` live in, kept mapped for as long as the error is; Mojo would otherwise unload it at the last handle's last use, while the error is still being read.

Conforms to

Copyable, Deinitable, ImplicitlyCopyable, Movable, Writable

__init__A failure the binding caught before any engine could name it.

def __init__(out self, status: Status, detail: StringSpan[ImmStaticOrigin])

Parameters

`statusStatus`		Which class of failure it is.
`detailStringSpan[ImmStaticOrigin]`		The entry point or binding type it was about.

write_toWrites the status name, the entry point, and the engine's own message together.

def write_to(self, mut writer: T)

Parameters

`writerT`	mut	The sink the message is appended to.