GSocketControlMessage: GIO Reference Manual

GSocketControlMessage

GSocketControlMessage — A GSocket control message

Functions

GSocketControlMessage *	g_socket_control_message_deserialize ()
int	g_socket_control_message_get_level ()
int	g_socket_control_message_get_msg_type ()
gsize	g_socket_control_message_get_size ()
void	g_socket_control_message_serialize ()

Types and Values

GSocketControlMessage

Object Hierarchy

    GObject
    ╰── GSocketControlMessage
        ├── GUnixCredentialsMessage
        ╰── GUnixFDMessage

Includes

#include <gio/gio.h>

Description

A GSocketControlMessage is a special-purpose utility message that can be sent to or received from a GSocket. These types of messages are often called "ancillary data".

The message can represent some sort of special instruction to or information from the socket or can represent a special kind of transfer to the peer (for example, sending a file descriptor over a UNIX socket).

These messages are sent with g_socket_send_message() and received with g_socket_receive_message().

To extend the set of control message that can be sent, subclass this class and override the get_size, get_level, get_type and serialize methods.

To extend the set of control messages that can be received, subclass this class and implement the deserialize method. Also, make sure your class is registered with the GType typesystem before calling g_socket_receive_message() to read such a message.

Functions

g_socket_control_message_deserialize ()

GSocketControlMessage *
g_socket_control_message_deserialize (int level,
                                      int type,
                                      gsize size,
                                      gpointer data);

Tries to deserialize a socket control message of a given level and type . This will ask all known (to GType) subclasses of GSocketControlMessage if they can understand this kind of message and if so deserialize it into a GSocketControlMessage.

If there is no implementation for this kind of control message, NULL will be returned.

Parameters

level	a socket level
type	a socket control message type for the given `level`
size	the size of the data in bytes
data	pointer to the message data.	[array length=size][element-type guint8]

Returns

the deserialized message or NULL.

[transfer full]

Since: 2.22

g_socket_control_message_get_level ()

int
g_socket_control_message_get_level (GSocketControlMessage *message);

Returns the "level" (i.e. the originating protocol) of the control message. This is often SOL_SOCKET.

Parameters

message

a GSocketControlMessage

Returns

an integer describing the level

Since: 2.22

g_socket_control_message_get_msg_type ()

int
g_socket_control_message_get_msg_type (GSocketControlMessage *message);

Returns the protocol specific type of the control message. For instance, for UNIX fd passing this would be SCM_RIGHTS.

Parameters

message

a GSocketControlMessage

Returns

an integer describing the type of control message

Since: 2.22

g_socket_control_message_get_size ()

gsize
g_socket_control_message_get_size (GSocketControlMessage *message);

Returns the space required for the control message, not including headers or alignment.

Parameters

message

a GSocketControlMessage

Returns

The number of bytes required.

Since: 2.22

g_socket_control_message_serialize ()

void
g_socket_control_message_serialize (GSocketControlMessage *message,
                                    gpointer data);

Converts the data in the message to bytes placed in the message.

data is guaranteed to have enough space to fit the size returned by g_socket_control_message_get_size() on this object.

Parameters

message	a GSocketControlMessage
data	A buffer to write data to.	[not nullable]

Since: 2.22

Types and Values