luc14n0/glib
1
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/glib.git synced 2025-12-20 07:05:17 +01:00
Code Issues Packages Projects Releases Wiki Activity

Clarify some GSocket docs

Browse Source
This commit is contained in:
Dan Winship
2009-05-23 21:49:47 -03:00
parent 5b3d62a7a6
commit 1ca91a2125
1 changed files with 118 additions and 96 deletions
Download Patch File Download Diff File Expand all files Collapse all files

214
gio/gsocket.c
View File

@@ -889,20 +889,23 @@ g_socket_get_blocking (GSocket *socket)
/** /**
* g_socket_set_keepalive: * g_socket_set_keepalive:
* @socket: a #GSocket. * @socket: a #GSocket.
* @keepalive: Whether to use try to keep the connection alive or not. * @keepalive: Value for the keepalive flag
* *
* Setting @keepalive to %TRUE enables the sending of periodic ping requests * Sets or unsets the %SO_KEEPALIVE flag on the underlying socket. When
* on idle connections in order to keep the connection alive. This is only * this flag is set on a socket, the system will attempt to verify that the
* useful for connection oriented sockets. The exact period used between * remote socket endpoint is still present if a sufficiently long period of
* each ping is system and protocol dependent. * time passes with no data being exchanged. If the system is unable to
* verify the presence of the remote endpoint, it will automatically close
* the connection.
* *
* Sending keepalive requests like this has a few disadvantages. For instance, * This option is only functional on certain kinds of sockets. (Notably,
* it uses more network bandwidth, and it makes your application more sensitive * %G_SOCKET_PROTOCOL_TCP sockets.)
* to temporary outages in the network (i.e. if a cable is pulled your otherwise *
* idle connection could be terminated, whereas otherwise it would survive unless * The exact time between pings is system- and protocol-dependent, but will
* actually used before the cable was reinserted). However, it is sometimes * normally be at least two hours. Most commonly, you would set this flag
* useful to ensure that connections are eventually terminated if e.g. the * on a server socket if you want to allow clients to remain idle for long
* remote side is disconnected, so as to avoid leaking resources forever. * periods of time, but also want to ensure that connections are eventually
* garbage-collected if clients crash or become unreachable.
* *
* Since: 2.22 * Since: 2.22
*/ */
@@ -1215,16 +1218,17 @@ g_socket_listen (GSocket *socket,
* *
* It is generally required to bind to a local address before you can * It is generally required to bind to a local address before you can
* receive connections. (See g_socket_listen() and g_socket_accept() ). * receive connections. (See g_socket_listen() and g_socket_accept() ).
* In certain situations, you may also want to bind a socket that will be
* used to initiate connections, though this is not normally required.
* *
* If @allow_reuse is %TRUE this allows the bind call to succeed in some * @allow_reuse should be %TRUE for server sockets (sockets that you will
* situation where it would otherwise return a %G_IO_ERROR_ADDRESS_IN_USE * eventually call g_socket_accept() on), and %FALSE for client sockets.
* error. The main example is for a TCP server socket where there are * (Specifically, if it is %TRUE, then g_socket_bind() will set the
* outstanding connections in the WAIT state, which are generally safe * %SO_REUSEADDR flag on the socket, allowing it to bind @address even if
* to ignore. However, setting it to %TRUE doesn't mean the call will * that address was previously used by another socket that has not yet been
* succeed if there is a socket actively bound to the address. * fully cleaned-up by the kernel. Failing to set this flag on a server
* * socket may cause the bind call to return %G_IO_ERROR_ADDRESS_IN_USE if
* In general, pass %TRUE if the socket will be used to accept connections, * the server program is stopped and then immediately restarted.)
* otherwise pass %FALSE.
* *
* Returns: %TRUE on success, %FALSE on error. * Returns: %TRUE on success, %FALSE on error.
* *
@@ -1513,21 +1517,29 @@ g_socket_check_connect_result (GSocket *socket,
* @socket: a #GSocket * @socket: a #GSocket
* @buffer: a buffer to read data into (which should be at least @size * @buffer: a buffer to read data into (which should be at least @size
* bytes long). * bytes long).
* @size: the number of bytes that will be read from the stream * @size: the number of bytes you want to read from the socket
* @error: #GError for error reporting, or %NULL to ignore. * @error: #GError for error reporting, or %NULL to ignore.
* *
* Receive data (up to @size bytes) from a socket. This is mainly used by * Receive data (up to @size bytes) from a socket. This is mainly used by
* connection oriented sockets, it is identical to g_socket_receive_from() * connection-oriented sockets; it is identical to g_socket_receive_from()
* with @address set to %NULL. * with @address set to %NULL.
* *
* If a message is too long to fit in @buffer, excess bytes may be discarded * For %G_SOCKET_TYPE_DATAGRAM and %G_SOCKET_TYPE_SEQPACKET sockets,
* depending on the type of socket the message is received from. * g_socket_receive() will always read either 0 or 1 complete messages from
* the socket. If the received message is too large to fit in @buffer, then
* the data beyond @size bytes will be discarded, without any explicit
* indication that this has occurred.
*
* For %G_SOCKET_TYPE_STREAM sockets, g_socket_receive() can return any
* number of bytes, up to @size. If more than @size bytes have been
* received, the additional data will be returned in future calls to
* g_socket_receive().
* *
* If the socket is in blocking mode the call will block until there is * If the socket is in blocking mode the call will block until there is
* some data to receive or there is an error. If there is no data available * some data to receive or there is an error. If there is no data available
* and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error * and the socket is in non-blocking mode, a %G_IO_ERROR_WOULD_BLOCK error
* will be returned. To be notified of available data, wait for the %G_IO_IN * will be returned. To be notified when data is available, wait for the
* condition. * %G_IO_IN condition.
* *
* On error -1 is returned and @error is set accordingly. * On error -1 is returned and @error is set accordingly.
* *
@@ -1596,7 +1608,7 @@ g_socket_receive (GSocket *socket,
* @address: a pointer to a #GSocketAddress pointer, or %NULL * @address: a pointer to a #GSocketAddress pointer, or %NULL
* @buffer: a buffer to read data into (which should be at least @size * @buffer: a buffer to read data into (which should be at least @size
* bytes long). * bytes long).
* @size: the number of bytes that will be read from the stream * @size: the number of bytes you want to read from the socket
* @error: #GError for error reporting, or %NULL to ignore. * @error: #GError for error reporting, or %NULL to ignore.
* *
* Receive data (up to @size bytes) from a socket. * Receive data (up to @size bytes) from a socket.
@@ -1605,13 +1617,7 @@ g_socket_receive (GSocket *socket,
* source address of the received packet. * source address of the received packet.
* @address is owned by the caller. * @address is owned by the caller.
* *
* If the socket is in blocking mode the call will block until there is * See g_socket_receive() for additional information.
* some data to receive or there is an error. If there is no data available
* and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error
* will be returned. To be notified of available data, wait for the %G_IO_IN
* condition.
*
* On error -1 is returned and @error is set accordingly.
* *
* Returns: Number of bytes read, or -1 on error * Returns: Number of bytes read, or -1 on error
* *
@@ -1643,24 +1649,23 @@ g_socket_receive_from (GSocket *socket,
* @size: the number of bytes to send * @size: the number of bytes to send
* @error: #GError for error reporting, or %NULL to ignore. * @error: #GError for error reporting, or %NULL to ignore.
* *
* Tries to send @size bytes from @buffer on the socket. * Tries to send @size bytes from @buffer on the socket. This is
* This is mainly used by connection oriented sockets, it is identical * mainly used by connection-oriented sockets; it is identical to
* to g_socket_send_to() with @address set to %NULL. * g_socket_send_to() with @address set to %NULL.
* *
* If the socket is in blocking mode the call will block until there is * If the socket is in blocking mode the call will block until there is
* space for the data in the socket queue. If there is no space available * space for the data in the socket queue. If there is no space available
* and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error * and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error
* will be returned. To be notified of available space, wait for the * will be returned. To be notified when space is available, wait for the
* %G_IO_OUT condition. * %G_IO_OUT condition. Note though that you may still receive
* * %G_IO_ERROR_WOULD_BLOCK from g_socket_send() even if you were previously
* Note that on Windows you can't rely on a %G_IO_OUT condition * notified of a %G_IO_OUT condition. (On Windows in particular, this is
* not producing a %G_IO_ERROR_WOULD_BLOCK error, as this is how Winsock * very common due to the way the underlying APIs work.)
* write notification works. However, robust apps should always be able to
* handle this since it can easily appear in other cases too.
* *
* On error -1 is returned and @error is set accordingly. * On error -1 is returned and @error is set accordingly.
* *
* Returns: Number of bytes read, or -1 on error * Returns: Number of bytes written (which may be less than @size), or -1
* on error
* *
* Since: 2.22 * Since: 2.22
*/ */
@@ -1731,20 +1736,10 @@ g_socket_send (GSocket *socket,
* %NULL then the message is sent to the default receiver (set by * %NULL then the message is sent to the default receiver (set by
* g_socket_connect()). * g_socket_connect()).
* *
* If the socket is in blocking mode the call will block until there is * See g_socket_send() for additional information.
* space for the data in the socket queue. If there is no space available
* and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error
* will be returned. To be notified of available space, wait for the %G_IO_OUT
* condition.
* *
* Note that on Windows you can't rely on a %G_IO_OUT condition * Returns: Number of bytes written (which may be less than @size), or -1
* not producing a %G_IO_ERROR_WOULD_BLOCK error, as this is how Winsock * on error
* write notification works. However, robust apps should always be able to
* handle this since it can easily appear in other cases too.
*
* On error -1 is returned and @error is set accordingly.
*
* Returns: Number of bytes read, or -1 on error
* *
* Since: 2.22 * Since: 2.22
*/ */
@@ -1851,13 +1846,29 @@ g_socket_shutdown (GSocket *socket,
* to complete even if the close returns with no error. * to complete even if the close returns with no error.
* *
* Once the socket is closed, all other operations will return * Once the socket is closed, all other operations will return
* %G_IO_ERROR_CLOSED. Closing a stream multiple times will not * %G_IO_ERROR_CLOSED. Closing a socket multiple times will not
* return an error. * return an error.
* *
* Sockets will be automatically closed when the last reference * Sockets will be automatically closed when the last reference
* is dropped, but you might want to call this function to make sure * is dropped, but you might want to call this function to make sure
* resources are released as early as possible. * resources are released as early as possible.
* *
* Beware that due to the way that TCP works, it is possible for
* recently-sent data to be lost if either you close a socket while the
* %G_IO_IN condition is set, or else if the remote connection tries to
* send something to you after you close the socket but before it has
* finished reading all of the data you sent. There is no easy generic
* way to avoid this problem; the easiest fix is to design the network
* protocol such that the client will never send data "out of turn".
* Another solution is for the server to half-close the connection by
* calling g_socket_shutdown() with only the @shutdown_write flag set,
* and then wait for the client to notice this and close its side of the
* connection, after which the server can safely call g_socket_close().
* (This is what #GTcpConnection does if you call
* g_tcp_connection_set_graceful_disconnect(). But of course, this
* only works if the client will close its connection after the server
* does.)
*
* Returns: %TRUE on success, %FALSE on error * Returns: %TRUE on success, %FALSE on error
* *
* Since: 2.22 * Since: 2.22
@@ -2437,11 +2448,14 @@ g_socket_condition_wait (GSocket *socket,
* If @address is %NULL then the message is sent to the default receiver * If @address is %NULL then the message is sent to the default receiver
* (set by g_socket_connect()). * (set by g_socket_connect()).
* *
* @vector must point to an array of #GOutputVector structs and * @vectors must point to an array of #GOutputVector structs and
* @num_vectors must be the length of this array. These structs * @num_vectors must be the length of this array. (If @num_vectors is -1,
* describe the buffers that the sent data will be gathered from. * then @vectors is assumed to be terminated by a #GOutputVector with a
* If @num_vector is -1, then @vector is assumed to be terminated * %NULL buffer pointer.) The #GOutputVector structs describe the buffers
* by a #GOutputVector with a %NULL buffer pointer. * that the sent data will be gathered from. Using multiple
* #GOutputVector<!-- -->s is more memory-efficient than manually copying
* data from multiple sources into a single buffer, and more
* network-efficient than making multiple calls to g_socket_send().
* *
* @messages, if non-%NULL, is taken to point to an array of @num_messages * @messages, if non-%NULL, is taken to point to an array of @num_messages
* #GSocketControlMessage instances. These correspond to the control * #GSocketControlMessage instances. These correspond to the control
@@ -2449,25 +2463,24 @@ g_socket_condition_wait (GSocket *socket,
* If @num_messages is -1 then @messages is treated as a %NULL-terminated * If @num_messages is -1 then @messages is treated as a %NULL-terminated
* array. * array.
* *
* @flags modify how the message sent. The commonly available arguments * @flags modify how the message is sent. The commonly available arguments
* for this is available in the #GSocketMsgFlags enum, but the * for this are available in the #GSocketMsgFlags enum, but the
* values there are the same as the system values, and the flags * values there are the same as the system values, and the flags
* are passed in as-is, so you can pass in system specific flags too. * are passed in as-is, so you can pass in system-specific flags too.
* *
* If the socket is in blocking mode the call will block until there is * If the socket is in blocking mode the call will block until there is
* space for the data in the socket queue. If there is no space available * space for the data in the socket queue. If there is no space available
* and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error * and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error
* will be returned. To be notified of available space, wait for the %G_IO_OUT * will be returned. To be notified when space is available, wait for the
* condition. * %G_IO_OUT condition. Note though that you may still receive
* * %G_IO_ERROR_WOULD_BLOCK from g_socket_send() even if you were previously
* Note that on Windows you can't rely on a %G_IO_OUT condition * notified of a %G_IO_OUT condition. (On Windows in particular, this is
* not producing a %G_IO_ERROR_WOULD_BLOCK error, as this is how Winsock * very common due to the way the underlying APIs work.)
* write notification works. However, robust apps should always be able to
* handle this since it can easily appear in other cases too.
* *
* On error -1 is returned and @error is set accordingly. * On error -1 is returned and @error is set accordingly.
* *
* Returns: Number of bytes read, or -1 on error * Returns: Number of bytes written (which may be less than @size), or -1
* on error
* *
* Since: 2.22 * Since: 2.22
*/ */
@@ -2720,21 +2733,21 @@ g_socket_send_message (GSocket *socket,
* @vector must point to an array of #GInputVector structs and * @vector must point to an array of #GInputVector structs and
* @num_vectors must be the length of this array. These structs * @num_vectors must be the length of this array. These structs
* describe the buffers that received data will be scattered into. * describe the buffers that received data will be scattered into.
* If @num_vector is -1, then @vector is assumed to be terminated * If @num_vectors is -1, then @vectors is assumed to be terminated
* by a #GInputVector with a %NULL buffer pointer. * by a #GInputVector with a %NULL buffer pointer.
* *
* As a special case, if the size of the array is zero (in which case, * As a special case, if @num_vectors is 0 (in which case, @vectors
* @vectors may of course be %NULL), then a single byte is received * may of course be %NULL), then a single byte is received and
* and discarded. This is to facilitate the common practice of * discarded. This is to facilitate the common practice of sending a
* sending a single '\0' byte for the purposes of transferring * single '\0' byte for the purposes of transferring ancillary data.
* ancillary data.
* *
* @messages, if non-%NULL, is taken to point to a pointer that will * @messages, if non-%NULL, will be set to point to a newly-allocated
* be set to point to a newly-allocated array of * array of #GSocketControlMessage instances. These correspond to the
* #GSocketControlMessage instances. These correspond to the control * control messages received from the kernel, one
* messages received from the kernel, one #GSocketControlMessage per * #GSocketControlMessage per message from the kernel. This array is
* message from the kernel. This array is %NULL-terminated and must be * %NULL-terminated and must be freed by the caller using g_free(). If
* freed by the caller using g_free(). * @messages is %NULL, any control messages received will be
* discarded.
* *
* @num_messages, if non-%NULL, will be set to the number of control * @num_messages, if non-%NULL, will be set to the number of control
* messages received. * messages received.
@@ -2744,15 +2757,24 @@ g_socket_send_message (GSocket *socket,
* in @messages (ie: not including the %NULL terminator). * in @messages (ie: not including the %NULL terminator).
* *
* @flags is an in/out parameter. The commonly available arguments * @flags is an in/out parameter. The commonly available arguments
* for this is available in the #GSocketMsgFlags enum, but the * for this are available in the #GSocketMsgFlags enum, but the
* values there are the same as the system values, and the flags * values there are the same as the system values, and the flags
* are passed in as-is, so you can pass in system specific flags too. * are passed in as-is, so you can pass in system-specific flags too
* (and g_socket_receive_message() may pass system-specific flags out).
* *
* If the socket is in blocking mode the call will block until there is * As with g_socket_receive(), data may be discarded if @socket is
* some data to receive or there is an error. If there is no data available * %G_SOCKET_TYPE_DATAGRAM or %G_SOCKET_TYPE_SEQPACKET and you do not
* and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error * provide enough buffer space to read a complete message. You can pass
* will be returned. To be notified of available data, wait for the %G_IO_IN * %G_SOCKET_MSG_PEEK in @flags to peek at the current message without
* condition. * removing it from the receive queue, but there is no portable way to find
* out the length of the message other than by reading it into a
* sufficiently-large buffer.
*
* If the socket is in blocking mode the call will block until there
* is some data to receive or there is an error. If there is no data
* available and the socket is in non-blocking mode, a
* %G_IO_ERROR_WOULD_BLOCK error will be returned. To be notified when
* data is available, wait for the %G_IO_IN condition.
* *
* On error -1 is returned and @error is set accordingly. * On error -1 is returned and @error is set accordingly.
* *