Runtime-sink-file-append-mode

Read the current append-mode policy used by a file-backed RuntimeSink. This helper exposes whether future reopen behavior is currently append-oriented on the runtime sink itself.

Interface

pub fn RuntimeSink::file_append_mode(self : RuntimeSink) -> Bool {

input

• self : RuntimeSink - Runtime sink 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

• Plain File runtime variants report the current append policy from the wrapped FileSink.
• QueuedFile runtime variants forward the policy from the wrapped inner FileSink.
• Non-file runtime variants 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 Direct Runtime Append-policy Visibility

When diagnostics should show how future reopen behavior is configured on a RuntimeSink:

let append = sink.file_append_mode()

In this example, the runtime sink exposes current reopen policy directly.

When Validate Direct Policy Changes

When policy mutation should be observable after a direct setter call:

ignore(sink.file_set_append_mode(true))
ignore(sink.file_append_mode())

In this example, callers verify the updated append-mode policy on the runtime sink itself.

Error Case

e.g.:

• If the runtime 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 direct runtime file behavior.