On Sunday 11 December 2005 01:43, Travis Miller wrote:
> Hello,
>
> I am trying to use GIOChannel in order to use sockets in a simple way (I
> am trying to get notification on events like read and disconnect).
> Anyway, here is the code that creates the GIOCHannel
>
> void
> on_ListenButton_clicked (GtkButton *button,
> gpointer user_data)
> {
> GtkWidget *text = lookup_widget(GTK_WIDGET(button),
> "StatusText");
>
> // create the listening socket
> int sockfd, new_fd;
> struct sockaddr_in my_addr;
> struct sockaddr_in their_addr;
> int sin_size;
>
> if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
> perror("socket");
> exit(1);
> }
>
> my_addr.sin_family = AF_INET;
> my_addr.sin_port = htons(1352);
> my_addr.sin_addr.s_addr = INADDR_ANY;
> bzero(&(my_addr.sin_zero), 8);
>
> if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct
> sockaddr)) == -1) {
> perror("bind");
> exit(1);
> }
>
>
> if (listen(sockfd, 5) == -1) {
> perror("listen");
> exit(1);
> }
> gtk_entry_set_text(GTK_ENTRY(text), "Listening");
>
> sin_size = sizeof(struct sockaddr_in);
> if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr,
> &sin_size)) == -1) {
> perror("accept");
> }
>
> // we got a socket so set text box
> gtk_entry_set_text(GTK_ENTRY(text), "Connection accepted");
>
> // now create GIOChannel from connection
> GIOChannel *iochannel = g_io_channel_unix_new(new_fd);
>
> // now add to main event loop
> GtkWidget *window = lookup_widget(GTK_WIDGET(button),
> "MainWindow");
> g_io_add_watch(iochannel, G_IO_IN, (GIOFunc *) &ReceiveData,
> (gpointer) window);
>
>
> // now close the listener
> close(sockfd);
>
> }
>
> The function g_io_watch() ties to the G_IO_IN (there is data to read on
> the socket) event to the function ReceiveData that is defined as
>
> gboolean ReceiveData(GIOChannel *source, GIOCondition condition,
> gpointer data)
> {
> gchar buf[500];
> int bytes_read;
> GtkWidget *text = NULL;
> GQuark quark;
> GError *error = NULL;
> gint sd;
>
>
>
> g_print("data received\n");
> text = lookup_widget(GTK_WIDGET(data), "StatusText");
> gtk_entry_set_text(GTK_ENTRY(text), "received data");
>
> sd = g_io_channel_unix_get_fd(source);
>
> bytes_read = recv(sd, buf, 500, 0);
>
> if(bytes_read == -1) {
> g_print("error\n");
> }
> else {
> buf[bytes_read] = '\0';
> g_print("buf = %s\n", buf);
> text = lookup_widget(GTK_WIDGET(data), "ReceivedText");
> gtk_entry_set_text(GTK_ENTRY(text), buf);
> }
>
> return TRUE;
> }
>
> The problem is this. If the client closes the connection then I get a
> flood of empty buffers and the ReceiveData() function is repeatedly
> called. What could cause this weird behavior?
I cannot see where you disconnect the callback. The easiest way to do that is
to call g_io_channel_unref() on the iochannel pointer immediately after you
have called g_io_add_watch() on it. g_io_channel_unix_new() returns a
GIOChannel object with a reference count of one. g_io_add_watch() adds a
further reference count - if you decrement it by 1, the callback will be
disconnected and the relevant GSource object removed as soon either the
callback returns FALSE or you call g_source_remove() on the return value of
g_io_add_watch() - so detect the closing of the socket by the peer in the
callback (read()/recv() returning 0 and/or the G_IO_HUP condition arising in
your 'condition' variable) and return FALSE upon that occurring, or store the
return value of g_io_add_watch() and call g_source_remove() on it.
For the result you mention to occur, it appears therefore that specifying the
G_IO_IN condition flag in g_io_add_watch() will cause the callback to be
called even if the the socket is in error condition or the socket is closed,
without actually specifying the G_IO_HUP or G_IO_ERR flags.
Chris
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