BitLogger/docs/api/configured-logger-file-flush.md

---
name: configured-logger-file-flush
group: api
category: runtime
update-time: 20260512
description: Flush the file sink behind a configured runtime logger when one is present.
key-word:
    - logger
    - runtime
    - file
    - public
---

## Configured-logger-file-flush

Flush the file sink behind a `ConfiguredLogger`. This helper is the file-specific runtime flush surface for config-built file loggers.

### Interface

```moonbit
pub fn ConfiguredLogger::file_flush(self : ConfiguredLogger) -> Bool {}
```

#### input

- `self : ConfiguredLogger` - Config-driven runtime logger whose file sink should be flushed.

#### output

- `Bool` - Whether the underlying file flush succeeded.

### Explanation

Detailed rules explaining key parameters and behaviors

- Plain file sinks forward directly to file flush behavior.
- Queued file sinks first flush queued records, then flush the wrapped file sink.
- Non-file sinks return `false`.
- This helper is narrower than generic `flush()` because it targets file sink behavior specifically.

### How to Use

Here are some specific examples provided.

#### When Need Explicit File Durability Steps

When a config-built file logger should flush to disk explicitly:
```moonbit
ignore(logger.file_flush())
```

In this example, the file-backed runtime sink is flushed directly through the configured logger.

#### When Need A File-specific Success Flag

When code should branch on the outcome of a file flush:
```moonbit
let ok = logger.file_flush()
```

In this example, callers can distinguish file flush success from a non-file sink shape.

### Error Case

e.g.:
- If the configured sink is not file-backed, the method returns `false`.

- If callers want generic queue or sink advancement instead of file-specific behavior, `flush()` is the broader API.

### Notes

1. Prefer this helper when the configured sink is known to be file-backed.

2. Queued file sinks may perform both queue flush and file flush work here.