GTK+ Forums

Hello,

I am new to GTK+ and have had problems printing to the text view buffer. Below is a piece of code which appears to have heap issues in the "go_build" function. Is there a problem with my implementation of the text view box or is this an issue within the GTK lib?

Note: If you remove the "int i" declaration after GtkTextBuffer *buffer and GtkTextIter *iter the code runs without a problem.

Thanks


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

static GtkWidget *status_message_area;

void init_user_window();
void go_build(GtkWidget *button);

int main(int argc, char** argv) {

gtk_init(&argc, &argv);
init_user_window();
gtk_main();

return (EXIT_SUCCESS);
}

void init_user_window()
{
GtkWidget *window;
GtkWidget *vbox1;
GtkWidget *vbox2;
GtkWidget *hbox1;
GtkWidget *build_button;
GtkWidget *exit_button;
GtkWidget *frame;
GtkWidget *scrolled_window1;

window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "Hello");
g_signal_connect(G_OBJECT(window), "destroy",
G_CALLBACK (gtk_widget_destroyed), NULL);
g_signal_connect(G_OBJECT(window), "delete_event",
G_CALLBACK(gtk_main_quit), NULL);

vbox1 = gtk_vbox_new(FALSE, 0);
gtk_container_add(GTK_CONTAINER(window), vbox1);

hbox1 = gtk_hbox_new(TRUE, 0);
gtk_box_pack_start(GTK_BOX(vbox1), hbox1, TRUE, TRUE, 15);

vbox2 = gtk_vbox_new(FALSE, 0);
gtk_box_pack_start(GTK_BOX(hbox1), vbox2, TRUE, TRUE, 30);

/*
* Add Exit Button
*/
exit_button = gtk_button_new_with_label("Exit");
gtk_box_pack_start(GTK_BOX(vbox2), exit_button, TRUE, TRUE, 0);
g_signal_connect(exit_button, "clicked",
G_CALLBACK (gtk_main_quit), NULL);
/*
* Add Build Button
*/
build_button = gtk_button_new_with_label("Build");
gtk_box_pack_start(GTK_BOX(vbox2), build_button, TRUE, TRUE, 0);
g_signal_connect(build_button, "clicked",
G_CALLBACK (go_build), NULL);
/*
* Add the status text area at the bottom of the window
*/
frame = gtk_frame_new("Status:");
gtk_widget_set_usize(frame, 480, 100);
gtk_box_pack_start(GTK_BOX(vbox1), frame, TRUE, TRUE, 0);
gtk_frame_set_shadow_type(GTK_FRAME(frame), GTK_SHADOW_OUT);

scrolled_window1 = gtk_scrolled_window_new(NULL, NULL);
gtk_container_add(GTK_CONTAINER(frame), scrolled_window1);
gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scrolled_window1),
GTK_POLICY_NEVER, GTK_POLICY_ALWAYS);

status_message_area = gtk_text_view_new();
gtk_container_add(GTK_CONTAINER(scrolled_window1), status_message_area);
gtk_text_view_set_editable(GTK_TEXT_VIEW(status_message_area), FALSE);
gtk_text_view_set_wrap_mode(GTK_TEXT_VIEW(status_message_area),
GTK_WRAP_WORD);

gtk_widget_show_all(window);
}


void go_build(GtkWidget *button)
{
const gchar *status_message = "Building...\n";

GtkTextBuffer *buffer;
GtkTextIter *iter;
int i;

buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(status_message_area));
gtk_text_buffer_get_end_iter(buffer, iter);
gtk_text_buffer_insert(buffer, iter, status_message, -1);
}

Hi,

Yes you are right that you have heap problems with your code. Your function go_build should look like this :-
Note the way GtkTextIter is used, it is created on the heap and not a pointer. Your previous code would have had a pointer that pointed to an unknown area of memory.

Also gtk_widget_set_usize () has been deprecated since GTK+ version 2.2 (which is now very old) and you should use gtk_widget_set_size_request () instead.

Errol.

_________________
E.