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

Request an asynchronous write of buffer.length bytes from buffer into the stream.

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

During an async request no other sync and async calls are allowed, 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 written 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. on a partial I/O error, but generally we try to write as many bytes as requested.

You are guaranteed that this method will never fail with g_io_error_would_block - if this can't accept more data, the method will just wait until this changes.

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.

For the synchronous, blocking version of this function, see write.

Note that no copy of buffer will be made, so it must stay valid until callback is called. See write_bytes_async for a Bytes version that will automatically hold a reference to the contents (without copying) for the duration of the call.



A OutputStream.


the buffer containing the data to write.


the io priority of the request.


optional Cancellable object, null to ignore.


callback to call when the request is satisfied


the number of bytes to write


the data to pass to callback function