14.11Plumbers🔗 i

There is no guarantee that a flush callback will be called before a process terminates—either because the plumber is not the original plumber that is flushed by the default exit handler, or because the process is terminated forcibly (e.g., through a custodian shutdown).

Added in version 6.0.1.8 of package base.

Plumbers have no hierarchy (unlike custodians or inspectors), but a flush callback can be registered in one plumber to call plumber-flush-all with another plumber.

Added in version 6.0.1.8 of package base.

Added in version 6.0.1.8 of package base.

The flush callbacks to call are collected from plumber before the first one is called. If a flush callback registers a new flush callback, the new one is not called. If a flush callback raises an exception or otherwise escapes, then the remaining flush callbacks are not called.

Added in version 6.0.1.8 of package base.

Added in version 6.0.1.8 of package base.

The result flush handle represents the registration of the callback, and it can be used with plumber-flush-handle-remove! to unregister the callback.

The given proc is reachable from the flush handle, but if weak? is true, then plumber retains only a weak reference to the result flush handle (and thus proc).

When proc is called as a flush callback, it is passed the same value that is returned by plumber-add-flush! so that proc can conveniently unregister itself. The call of proc is within a continuation barrier.

Added in version 6.0.1.8 of package base.

If the registration represented by handle has been removed already, then plumber-flush-handle-remove! has no effect.

Added in version 6.0.1.8 of package base.