Method

GioInputStreamread_async

Declaration

void
g_input_stream_read_async (
  GInputStream* stream,
  void* buffer,
  gsize count,
  int io_priority,
  GCancellable* cancellable,
  GAsyncReadyCallback callback,
  gpointer user_data
)

Description

Request an asynchronous read of count bytes from the stream into the buffer starting at buffer. When the operation is finished callback will be called. You can then call g_input_stream_read_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 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 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.

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.

Parameters

buffer

Type: An array of guint8

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

The argument will be set by the function.
The length of the array is specified in the count argument.
The data is owned by the caller of the function.
count

Type: gsize

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

io_priority

Type: int

The [I/O priority][io-priority] of the request.

cancellable

Type: GCancellable

Optional GCancellable object, NULL to ignore.

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

Type: GAsyncReadyCallback

Callback to call when the request is satisfied.

The argument can be NULL.
user_data

Type: gpointer

The data to pass to callback function.

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