Asynchronously opens this for reading.
For more details, see read which is the synchronous version of this call.
When the operation is finished, callback will be called. You can then call read_async.end
to get the result of the operation.
| this |
input File |
| io_priority |
the I/O priority of the request |
| cancellable |
optional Cancellable object, null to ignore |
| callback |
a AsyncReadyCallback to call when the request is satisfied |
| user_data |
the data to pass to callback function |