尝试保持主循环忙时的段错误

Question

为了测试我对Gtk的其他部分的理解,我想编写一个程序,它总是有一个事件准备好主循环使用.我写了这个简短的程序来尝试这样做:

#include <gtk/gtk.h>

static void toggle(GtkWidget *check, gpointer data)
{
    gboolean checked;
    g_object_get(check, "active", &checked, NULL);
    g_object_set(check, "active", !checked, NULL);
}

int main(int argc, char *argv[])
{
    GtkWidget *window, *check;
    gtk_init(&argc, &argv);
    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    check  = gtk_check_button_new();
    g_signal_connect(check, "toggled", G_CALLBACK(toggle), NULL);
    gtk_container_add(GTK_CONTAINER(window), check);
    gtk_widget_show_all(window);
    gtk_main();
}

当我运行此程序并单击复选框时,它会出现段错误.是什么赋予了？保持主循环忙的正确方法是什么？

(旁注:它在segfaulting之前可靠地切换2048次 - 一个可疑的圆数.)

Answer 1

在你的toggle处理程序中,你正在设置checked,这会导致toggle发出一个信号,重新调用处理程序......

#11564 0xb775ba50 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#11565 0xb776e5d0 in ?? () from /usr/lib/libgobject-2.0.so.0
#11566 0xb77774d6 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#11567 0xb7777682 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#11568 0xb7e067ba in gtk_toggle_button_toggled ()

我没有完全遵循,但我可以看到> 11000帧将如何导致段错误.

回答你的另一个问题:我认为保持主循环充满的方法是通过g_idle_add()调用:

#include <gtk/gtk.h>

static void toggle(GtkWidget *check, gpointer data)
{
  g_print(".");
}

GtkWidget *window, *check;

static gboolean
toggle_it()
{
  gboolean checked;
  g_object_get(check, "active", &checked, NULL);
  g_object_set(check, "active", !checked, NULL);
  return TRUE;
}

int main(int argc, char *argv[])
{
    gtk_init(&argc, &argv);
    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    check  = gtk_check_button_new();
    g_signal_connect(check, "toggled", G_CALLBACK(toggle), NULL);
    gtk_container_add(GTK_CONTAINER(window), check);
    gtk_widget_show_all(window);
    g_idle_add((GSourceFunc)toggle_it, NULL);
    gtk_main();
}