Functions
g_pollable_output_stream_can_poll ()
gboolean
g_pollable_output_stream_can_poll (GPollableOutputStream *stream);
Checks if stream
is actually pollable. Some classes may implement
GPollableOutputStream but have only certain instances of that
class be pollable. If this method returns FALSE, then the behavior
of other GPollableOutputStream methods is undefined.
For any given stream, the value returned by this method is constant;
a stream cannot switch from pollable to non-pollable or vice versa.
Returns
TRUE if stream
is pollable, FALSE if not.
Since: 2.28
g_pollable_output_stream_write_nonblocking ()
gssize
g_pollable_output_stream_write_nonblocking
(GPollableOutputStream *stream,
const void *buffer,
gsize count,
GCancellable *cancellable,
GError **error);
Attempts to write up to count
bytes from buffer
to stream
, as
with g_output_stream_write(). If stream
is not currently writable,
this will immediately return G_IO_ERROR_WOULD_BLOCK, and you can
use g_pollable_output_stream_create_source() to create a GSource
that will be triggered when stream
is writable.
Note that since this method never blocks, you cannot actually
use cancellable
to cancel it. However, it will return an error
if cancellable
has already been cancelled when you call, which
may happen if you call this method after a source triggers due
to having been cancelled.
Also note that if G_IO_ERROR_WOULD_BLOCK is returned some underlying
transports like D/TLS require that you re-send the same buffer
and
count
in the next write call.
Virtual: write_nonblocking
g_pollable_output_stream_writev_nonblocking ()
GPollableReturn
g_pollable_output_stream_writev_nonblocking
(GPollableOutputStream *stream,
const GOutputVector *vectors,
gsize n_vectors,
gsize *bytes_written,
GCancellable *cancellable,
GError **error);
Attempts to write the bytes contained in the n_vectors
vectors
to stream
,
as with g_output_stream_writev(). If stream
is not currently writable,
this will immediately return %G_POLLABLE_RETURN_WOULD_BLOCK
, and you can
use g_pollable_output_stream_create_source() to create a GSource
that will be triggered when stream
is writable. error
will *not* be
set in that case.
Note that since this method never blocks, you cannot actually
use cancellable
to cancel it. However, it will return an error
if cancellable
has already been cancelled when you call, which
may happen if you call this method after a source triggers due
to having been cancelled.
Also note that if G_POLLABLE_RETURN_WOULD_BLOCK is returned some underlying
transports like D/TLS require that you re-send the same vectors
and
n_vectors
in the next write call.
Virtual: writev_nonblocking
Since: 2.60
Types and Values
GPollableOutputStream
typedef struct _GPollableOutputStream GPollableOutputStream;
An interface for a GOutputStream that can be polled for writeability.
Since: 2.28
struct GPollableOutputStreamInterface
struct GPollableOutputStreamInterface {
GTypeInterface g_iface;
/* Virtual Table */
gboolean (*can_poll) (GPollableOutputStream *stream);
gboolean (*is_writable) (GPollableOutputStream *stream);
GSource * (*create_source) (GPollableOutputStream *stream,
GCancellable *cancellable);
gssize (*write_nonblocking) (GPollableOutputStream *stream,
const void *buffer,
gsize count,
GError **error);
GPollableReturn (*writev_nonblocking) (GPollableOutputStream *stream,
const GOutputVector *vectors,
gsize n_vectors,
gsize *bytes_written,
GError **error);
};
The interface for pollable output streams.
The default implementation of can_poll
always returns TRUE.
The default implementation of write_nonblocking
calls
g_pollable_output_stream_is_writable(), and then calls
g_output_stream_write() if it returns TRUE. This means you only
need to override it if it is possible that your is_writable
implementation may return TRUE when the stream is not actually
writable.
The default implementation of writev_nonblocking
calls
g_pollable_output_stream_write_nonblocking() for each vector, and converts
its return value and error (if set) to a GPollableReturn. You should
override this where possible to avoid having to allocate a GError to return
G_IO_ERROR_WOULD_BLOCK.
Since: 2.28