Description
Provides a base class for implementing asynchronous function results.
Asynchronous operations are broken up into two separate operations
which are chained together by a GAsyncReadyCallback. To begin
an asynchronous operation, provide a GAsyncReadyCallback to the
asynchronous function. This callback will be triggered when the
operation has completed, and will be passed a GAsyncResult instance
filled with the details of the operation's success or failure, the
object the asynchronous function was started for and any error codes
returned. The asynchronous callback function is then expected to call
the corresponding "_finish()" function, passing the object the
function was called for, the GAsyncResult instance, and (optionally)
an error to grab any error conditions that may have occurred.
The "_finish()" function for an operation takes the generic result
(of type GAsyncResult) and returns the specific result that the
operation in question yields (e.g. a GFileEnumerator for a
"enumerate children" operation). If the result or error status of the
operation is not needed, there is no need to call the "_finish()"
function; GIO will take care of cleaning up the result and error
information after the GAsyncReadyCallback returns. Applications may
also take a reference to the GAsyncResult and call "_finish()"
later; however, the "_finish()" function may be called at most once.
Example of a typical asynchronous operation flow:
The callback for an asynchronous operation is called only once, and is
always called, even in the case of a cancelled operation. On cancellation
the result is a G_IO_ERROR_CANCELLED error.
Some asynchronous operations are implemented using synchronous calls.
These are run in a separate thread, if GThread has been initialized, but
otherwise they are sent to the Main Event Loop and processed in an idle
function. So, if you truly need asynchronous operations, make sure to
initialize GThread.
Description Provides a base class for implementing asynchronous function results. Asynchronous operations are broken up into two separate operations which are chained together by a GAsyncReadyCallback. To begin an asynchronous operation, provide a GAsyncReadyCallback to the asynchronous function. This callback will be triggered when the operation has completed, and will be passed a GAsyncResult instance filled with the details of the operation's success or failure, the object the asynchronous function was started for and any error codes returned. The asynchronous callback function is then expected to call the corresponding "_finish()" function, passing the object the function was called for, the GAsyncResult instance, and (optionally) an error to grab any error conditions that may have occurred. The "_finish()" function for an operation takes the generic result (of type GAsyncResult) and returns the specific result that the operation in question yields (e.g. a GFileEnumerator for a "enumerate children" operation). If the result or error status of the operation is not needed, there is no need to call the "_finish()" function; GIO will take care of cleaning up the result and error information after the GAsyncReadyCallback returns. Applications may also take a reference to the GAsyncResult and call "_finish()" later; however, the "_finish()" function may be called at most once. Example of a typical asynchronous operation flow: The callback for an asynchronous operation is called only once, and is always called, even in the case of a cancelled operation. On cancellation the result is a G_IO_ERROR_CANCELLED error. Some asynchronous operations are implemented using synchronous calls. These are run in a separate thread, if GThread has been initialized, but otherwise they are sent to the Main Event Loop and processed in an idle function. So, if you truly need asynchronous operations, make sure to initialize GThread.