Re: Executing external process goes into infinite loop

[RNG <rgasch gmail com>]

Hi,

thanks a lot for your tip. Replacing the gdk_input_add() call with
g_id_add_watch() seems to have cured the problem.

Greetings/Thanks
Robert

On Mon, May 4, 2009 at 5:35 PM, Ardhan Madras <ajhwb knac com> wrote:
> In execute_input() i can't see a code to make a infinite loop, If you are curious, see codes of 
> gdk_input_add() and find out why the GdkInputFunction recalled, btw have you try g_io_add_watch() instead 
> by making a call to gdk_input_add() the deprecated one?.
>
> --- ajhwb
>
>
> --- rgasch gmail com wrote:
>
> From: RNG <rgasch gmail com>
> To: gtk-app-devel-list gnome org
> Subject: Executing external process goes into infinite loop
> Date: Mon, 4 May 2009 08:52:56 +0200
>
> Hi,
>
> I have inherited an old version of a glade-based program which I am
> trying to clean up. I have applied some fixes and for the most part
> things are going well, but 1 function in particular is giving me
> trouble and I will readily admit that I don't quite understand how
> this is working and how it should work.
>
> The function in question calls a rendering process (povray) by calling
> the execute_command() function. This works but upon completion of the
> rendering process, my program goes into an infinite loop, continually
> calling the execute_input() function as if the end of the povray
> process is never detected. Below is the relevant code, I would be
> grateful as to any ideas what might be wrong here because as stated
> above, I am stumped.
>
> Thanks
> Robert
>
>
> -------------------------------------------------------------------------
>
>
> typedef struct ExecData ExecData;
> struct ExecData
> {
>  int           input;
>  gchar        *text;
>  gchar        *error_message;
>  FinishedFunc  finish_func;
>  gpointer      user_data;
>  gint          pid;
>  gint          input_id;
> };
>
> static ExecData *
> exec_data_new (int           in,
>               gchar        *error_msg,
>               FinishedFunc  func,
>               gpointer      user_data,
>               int           pid)
> {
>  ExecData *data;
>
>  data = g_new0 (ExecData, 1);
>  data->input = in;
>  data->text = g_strdup ("");
>  data->error_message = g_strdup (error_msg);
>  data->finish_func = func;
>  data->user_data = user_data;
>  data->pid = pid;
>
>  return data;
> }
>
> static void
> exec_data_free (ExecData *data)
> {
>  close (data->input);
>  g_free (data->error_message);
>  g_free (data->text);
>  g_free (data);
> }
>
> static void
> execute_input (gpointer          user_data,
>               gint              source_fd,
>               GdkInputCondition condition)
> {
>  ExecData *data = (ExecData*) user_data;
>  gchar     buf[1025];
>  gint      length;
>
>  fcntl (data->input, F_SETFL, O_NONBLOCK);
>  length = read (data->input, buf, 1024);
>  fcntl (data->input, F_SETFL, 0);
>  if (length <= 0)
>    {
>      if (length == 0 && errno != EAGAIN)
>        {
>          gchar *open_paren;
>          gint   status;
>
>          open_paren = strrchr (data->text, '(');
>          status = -1;
>          if (open_paren != NULL)
>          if (sscanf (&open_paren[1], "%i", &status) != 1)
>            status = -1;
>
>          /* POV-Ray returns 512 on an aborted trace.
>             Don't popup an error dialog box. */
>          if (status != 0 && status != 512)
>            {
>              GtkWidget *window;
>
>              window = create_execution_error_window ();
>
>              set_text (window, "error_label", data->error_message);
>              set_text (window, "error_text", data->text);
>              gtk_widget_show (window);
>            }
>
>          if (data->finish_func != NULL)
>            data->finish_func (data->user_data);
>
>          waitpid (data->pid, NULL, 0);
>
>          gdk_input_remove (data->input_id);
>          close (data->input);
>          exec_data_free (data);
>        }
>    }
>  else
>    {
>      buf[length] = '\0';
>      data->text =
>        g_renew (gchar, data->text, length + strlen (data->text) + 1);
>      strcat (data->text, buf);
>    }
> }
>
> void
> execute_command (gchar        *command,
>                 gchar        *error_message,
>                 FinishedFunc  func,
>                 gpointer      user_data)
> {
>  int       in;
>  ExecData *data;
>  int       pid;
>
>  in = proc_open (command, &pid);
>  data = exec_data_new (in, error_message, func, user_data, pid);
>
>  g_free (data->text);
>  data->text = g_strdup_printf ("Executing the command: '%s'\n\n", command);
>
>  data->input_id =
>    gdk_input_add (in,
>                   GDK_INPUT_READ,
>                   (GdkInputFunction) execute_input,
>                   (gpointer) data);
> }
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