loadContentsAsync
Starts an asynchronous load of the @file's contents.
For more details, see g_file_load_contents() which is the synchronous version of this call.
When the load operation has completed, @callback will be called with @user data. To finish the operation, call g_file_load_contents_finish() with the #GAsyncResult returned by the @callback.
If @cancellable is not null, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
Parameters
cancellable
optional #GCancellable object, null to ignore
callback
a #GAsyncReadyCallback to call when the request is satisfied