since: 2.34


g_input_stream_read_bytes_async (
  GInputStream* stream,
  gsize count,
  int io_priority,
  GCancellable* cancellable,
  GAsyncReadyCallback callback,
  gpointer user_data


Request an asynchronous read of count bytes from the stream into a new GBytes. When the operation is finished callback will be called. You can then call g_input_stream_read_bytes_finish() to get the result of the operation.

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

A value of count larger than G_MAXSSIZE will cause a G_IO_ERROR_INVALID_ARGUMENT error.

On success, the new GBytes will be passed to the callback. It is not an error if this is smaller than 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 count 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.

Available since: 2.34



Type: gsize

The number of bytes that will be read from the stream.


Type: int

The I/O priority of the request.


Type: GCancellable

Optional GCancellable object, NULL to ignore.

The argument can be NULL.
The data is owned by the caller of the function.

Type: GAsyncReadyCallback

A GAsyncReadyCallback to call when the request is satisfied.

The argument can be NULL.

Type: gpointer

The data to pass to callback function.

The argument can be NULL.
The data is owned by the caller of the function.