CODEWITHSUNDEEP
cgtk
user2063321
user2063321

Reputation:

Gtk gchar labelling

I keep getting this error and weird gibberish when I try to run the following snippet of code:

ERROR is:

(foo:11333): Pango-WARNING **: Invalid UTF-8 string passed to pango_layout_set_text()

Structure definition:

typedef struct chat_info ChatInfo;
struct chat_info {
  GtkWidget *text_line1;
  GtkWidget *text_line2;
  GtkWidget *text_line3;
  GtkWidget *entry;

};

And this code makes the weird gibberish come out on the third label (second label is empty)

static void send_message(GtkWidget *window, gpointer data){
    GuiInfo *g = (GuiInfo *) data;


    ChatInfo *c = g->chat;

    const gchar *message = gtk_entry_get_text(GTK_ENTRY(c->entry));  
    const gchar *oldtext1 = gtk_label_get_text( (GtkLabel *) c->text_line1);
    const gchar *oldtext2 = gtk_label_get_text( (GtkLabel *) c->text_line2);

    gtk_label_set_text( (GtkLabel *) c->text_line1, message);
    gtk_label_set_text( (GtkLabel *) c->text_line2, oldtext1);
    gtk_label_set_text( (GtkLabel *) c->text_line3, oldtext2);


}

I looked up the error, and I'm guessing it's probably due to something like giving a pointer address when I should be giving a gchar string? Everything looks right though.

Upvotes: 0

Views: 603

Answers (1)

Rob Bradford
Rob Bradford

Reputation: 1460

I believe the problem is that the memory that's coming back from your _get_text() calls is being freed by GtkLabel before you use it again by you calling _set_text().

For example when you call gtk_label_set_text(c->text_line1, message) that renders the pointer you retrieved into oldtext1 invalid (the call to gtk_label_get_text() returns a pointer to the internal copy of the string).

Now you can fix this by reordering your code to remove that dependency:

gtk_label_set_text( (GtkLabel *) c->text_line3, oldtext2);
gtk_label_set_text( (GtkLabel *) c->text_line2, oldtext1);
gtk_label_set_text( (GtkLabel *) c->text_line1, message);

Or perhaps for readability you should strdup() the strings you get from _get_text() and then pass those into _set_text() and free those later.

Upvotes: 4

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