public virtual async ssize_t read_async (uint8[]? buffer, int io_priority = DEFAULT, Cancellable? cancellable = null) throws IOError

Request an asynchronous read of buffer.length bytes from the stream into the buffer starting at buffer.

When the operation is finished callback will be called. You can then call read_async.end to get the result of the operation.

During an async request no other sync and async calls are allowed on this, and will result in g_io_error_pending errors.

A value of buffer.length larger than g_maxssize will cause a g_io_error_invalid_argument error.

On success, the number of bytes read into the buffer will be passed to the callback. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if buffer.length is zero), but never otherwise.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is g_priority_default.

The asynchronous methods have a default fallback that uses threads to implement asynchronicity, so they are optional for inheriting classes. However, if you override one you must override all.



A InputStream.


a buffer to read data into (which should be at least count bytes long).


the I/O priority of the request.


optional Cancellable object, null to ignore.


callback to call when the request is satisfied


the number of bytes that will be read from the stream


the data to pass to callback function