gio::prelude

Trait InitableExt

Source
pub trait InitableExt:
    IsA<Initable>
    + Sealed
    + 'static {
    // Provided method
    unsafe fn init(
        &self,
        cancellable: Option<&impl IsA<Cancellable>>,
    ) -> Result<(), Error> { ... }
}
Expand description

Provided Methods§

Source

unsafe fn init( &self, cancellable: Option<&impl IsA<Cancellable>>, ) -> Result<(), Error>

Initializes the object implementing the interface.

This method is intended for language bindings. If writing in C, g_initable_new() should typically be used instead.

The object must be initialized before any real use after initial construction, either with this function or g_async_initable_init_async().

Implementations may also support cancellation. If @cancellable is not None, then initialization can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error IOErrorEnum::Cancelled will be returned. If @cancellable is not None and the object doesn’t support cancellable initialization the error IOErrorEnum::NotSupported will be returned.

If the object is not initialized, or initialization returns with an error, then all operations on the object except g_object_ref() and g_object_unref() are considered to be invalid, and have undefined behaviour. See the [introduction][ginitable] for more details.

Callers should not assume that a class which implements #GInitable can be initialized multiple times, unless the class explicitly documents itself as supporting this. Generally, a class’ implementation of init() can assume (and assert) that it will only be called once. Previously, this documentation recommended all #GInitable implementations should be idempotent; that recommendation was relaxed in GLib 2.54.

If a class explicitly supports being initialized multiple times, it is recommended that the method is idempotent: multiple calls with the same arguments should return the same results. Only the first call initializes the object; further calls return the result of the first call.

One reason why a class might need to support idempotent initialization is if it is designed to be used via the singleton pattern, with a #GObjectClass.constructor that sometimes returns an existing instance. In this pattern, a caller would expect to be able to call g_initable_init() on the result of g_object_new(), regardless of whether it is in fact a new instance.

§cancellable

optional #GCancellable object, None to ignore.

§Returns

true if successful. If an error has occurred, this function will return false and set @error appropriately if present.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§