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Configured-logger-file-append-mode ​

Read the current append-mode policy used by a ConfiguredLogger file sink. This helper exposes whether future reopen behavior is currently append-oriented.

Interface ​

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

input ​

  • self : ConfiguredLogger - Config-driven runtime logger whose append-mode policy should be inspected.

output ​

  • Bool - Current append-mode policy for the file sink.

Explanation ​

Detailed rules explaining key parameters and behaviors

  • File-backed sinks report their current append policy through the wrapped RuntimeSink.
  • Queued file sinks forward the policy from the wrapped inner file sink.
  • Non-file sinks return false.
  • This helper reports runtime file policy, not whether a file is currently writable.

How to Use ​

Here are some specific examples provided.

When Need Runtime Append-policy Visibility ​

When diagnostics should show how future reopen behavior is configured:

moonbit
let append = logger.file_append_mode()

In this example, the configured logger exposes current reopen policy directly.

When Validate Runtime Policy Changes ​

When policy mutation should be observable after a setter call:

moonbit
ignore(logger.file_set_append_mode(true))
ignore(logger.file_append_mode())

In this example, callers verify the updated append-mode policy.

Error Case ​

e.g.:

  • If the configured sink is not file-backed, the method returns false.

  • If callers need the full current file policy rather than just append mode, file_policy() is the better API.

Notes ​

  1. Use this helper when append policy is the only file setting you need to inspect.

  2. Pair it with reopen helpers when debugging runtime file behavior.

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