Re: gtk_tree_model_filter_set_modify_func()

[Russell Shaw <rjshaw netspace net au>]

Tim Müller wrote:
> On Tuesday 29 June 2004 18:25, Russell Shaw wrote:
>
> > In the following code, i can only get printed on the terminal window:
> >   n:0 val:(null)
> > I should get:
> >   n:0 val:abc
> >
> > If i comment out the gtk_tree_model_filter_set_modify_func() line
> > then it works. What am i doing wrong? Gtk 2.4.3
>
>
> > ... snip ...
> >
> > void filtermodifyfunc(
> >                       GtkTreeModel *model,
> >                       GtkTreeIter *iter,
> >                       GValue *value,
> >                       gint column,
> >                       gpointer data)
> > {
> >     return;
> > }
>
>
> you're supposed to set the value to something in that function, otherwise it 
> will just stay initialised to 0/NULL ....

When i get the value to modify with gtk_tree_model_get() in the code below, it
seems to recursively call filtermodifyfunc() and the process repeats until a
segfault:

void filtermodifyfunc(
                      GtkTreeModel *model,
                      GtkTreeIter *iter,
                      GValue *value,
                      gint column,
                      gpointer data)
{
    g_printf("passed\n");
    if(G_VALUE_HOLDS_STRING(value)){
        gchar *str;
        gtk_tree_model_get(model,iter,column,&str,-1);
        g_value_set_string(value,str);
        g_printf(col:%d val:%s\n",column,str);
    }
    else if(G_VALUE_HOLDS_UINT(value)){
        guint n;
        gtk_tree_model_get(model,iter,column,&n,-1);
        g_value_set_uint(value,n);
        g_printf(col:%d n:%u\n",column,n);
    }
}

----------------------------------------------------------------------
Program:

#include <stdlib.h>
#include <stdio.h>
#include <gtk/gtk.h>
#include <gtk/gtksignal.h>
#include <string.h>

static
gboolean delete(
                GtkWidget *widget,
                GtkWidget *event,
                gpointer data)
{
    gtk_main_quit ();
}

void filtermodifyfunc(
                      GtkTreeModel *model,
                      GtkTreeIter *iter,
                      GValue *value,
                      gint column,
                      gpointer data)
{
    g_printf("passed\n");
    if(G_VALUE_HOLDS_STRING(value)){
        gchar *str;
        gtk_tree_model_get(model,iter,column,&str,-1);
        g_value_set_string(value,str);
        g_printf(col:%d val:%s\n",column,str);
    }
    else if(G_VALUE_HOLDS_UINT(value)){
        guint n;
        gtk_tree_model_get(model,iter,column,&n,-1);
        g_value_set_uint(value,n);
        g_printf(col:%d n:%u\n",column,n);
    }
}

gint main(gint argc, gchar *argv[])
{
    gtk_init (&argc, &argv);

    GtkWidget *window=gtk_window_new(GTK_WINDOW_TOPLEVEL);

    g_signal_connect(G_OBJECT(window),"delete_event",G_CALLBACK(delete),NULL);

    GtkListStore *store=gtk_list_store_new(2,G_TYPE_UINT,G_TYPE_STRING);

    GtkTreeIter iter;
    gtk_list_store_append(store,&iter);
    gtk_list_store_set(store,&iter,0,0,1,"abc",-1);
    gtk_list_store_append(store,&iter);
    gtk_list_store_set(store,&iter,0,1,1,"def",-1);
    gtk_list_store_append(store,&iter);
    gtk_list_store_set(store,&iter,0,2,1,"ghi",-1);

    GtkTreeModel *modelfilter=
                       gtk_tree_model_filter_new(GTK_TREE_MODEL(store),NULL);

    GType types[]={G_TYPE_UINT,G_TYPE_STRING};

    gtk_tree_model_filter_set_modify_func(
                        GTK_TREE_MODEL_FILTER(modelfilter),
                        2,
                        types,
                        filtermodifyfunc,
                        NULL,
                        NULL);

    gtk_tree_model_get_iter_first(GTK_TREE_MODEL(modelfilter),&iter);

    guint n;
    gchar *str1;
    gtk_tree_model_get(GTK_TREE_MODEL(modelfilter),&iter,0,&n,1,&str1,-1);

    g_printf("n:%d val:%s\n",n,str1);

    gtk_widget_show_all(window);

    gtk_main();

    return 0;
}