# ProcessError
<span class="source-link">[[Source]](src/process/process_error.md#L-0-1)</span>

Why a process could not be started, or why monitoring one failed.
`StartProcess` returns a `ProcessError` when it cannot start a process, and
`ProcessNotify.failed` receives one for errors that arise while a process
runs. `error_type` is the category of the error; `message` is optional
human-readable detail.


```pony
class val ProcessError
```

## Constructors

### create
<span class="source-link">[[Source]](src/process/process_error.md#L-0-12)</span>


```pony
new val create(
  error_type': ProcessErrorType,
  message': (String val | None val) = None)
: ProcessError val^
```
#### Parameters

*   error_type': [ProcessErrorType](process-ProcessErrorType.md)
*   message': ([String](builtin-String.md) val | [None](builtin-None.md) val) = None

#### Returns

* [ProcessError](process-ProcessError.md) val^

---

## Public fields

### let error_type: [ProcessErrorType](process-ProcessErrorType.md)
<span class="source-link">[[Source]](src/process/process_error.md#L-0-9)</span>



---

### let message: ([String](builtin-String.md) val | [None](builtin-None.md) val)
<span class="source-link">[[Source]](src/process/process_error.md#L-0-10)</span>



---

## Public Functions

### string
<span class="source-link">[[Source]](src/process/process_error.md#L-0-18)</span>


```pony
fun box string()
: String iso^
```

#### Returns

* [String](builtin-String.md) iso^

---

