c++ - (C++) Gtk-WARNING ** : Could not find signal handler'. 是否使用 -rdynamic 进行编译？

Question

我是使用 GTK+ 进行 C++ GUI 编程的新手，我在让其中一个按钮的信号处理程序正常工作时遇到问题，在编译和运行时我收到以下警告。有谁知道我是做错了什么还是遗漏了什么？

(Project Thoth:4359):Gtk-WARNING **:找不到信号处理程序“on_login_clicked”。你用 -rdynamic 编译了吗？

这是我的cpp文件

#include <cstdlib>
#include <cstdio>
#include <string>
#include <gtk/gtk.h>
#include <iostream>
extern "C"
using namespace std;

int main(int argc, char *argv[])
{
GtkEntry *e1;//textbox1
GtkEntry *e2;//textbox2
GtkEntry *e3;//textbox3

GtkBuilder *gtkBuilder;
GtkWidget *window;

gtk_init(&argc, &argv);

gtkBuilder = gtk_builder_new();
gtk_builder_add_from_file(gtkBuilder, "Unsaved 1.glade", NULL);
window = GTK_WIDGET(gtk_builder_get_object(gtkBuilder, "Login"));

gtk_builder_connect_signals(gtkBuilder, window);

g_object_unref(G_OBJECT(gtkBuilder));
gtk_widget_show(window);
gtk_main();
cout << "Login window loaded";
return 0;
}

G_MODULE_EXPORT void  on_login_clicked()
{
printf("Request Detected\n");
GtkBuilder  *gtkBuilder;
GtkWidget *window;

gtkBuilder = gtk_builder_new();
gtk_builder_add_from_file(gtkBuilder, "Unsaved 1.glade", NULL);

GtkEntry *e1;
GtkEntry *e2;
e1 = GTK_ENTRY( gtk_builder_get_object( gtkBuilder, "user1" ));
e2 = GTK_ENTRY( gtk_builder_get_object( gtkBuilder, "pass"));
gtk_builder_connect_signals(gtkBuilder, e1);
const char *home;
home = gtk_entry_get_text(e1);
cout << home;
}

还有我的林间空地文件

    <?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.18.3 -->
<interface>
  <requires lib="gtk+" version="3.0"/>
  <object class="GtkApplicationWindow" id="Login">
    <property name="can_focus">False</property>
    <property name="window_position">center</property>
    <property name="default_width">400</property>
    <property name="default_height">300</property>
    <signal name="destroy" handler="on_window_destroy" swapped="no"/>
    <child>
      <object class="GtkLayout" id="layout1">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <child>
          <object class="GtkLabel" id="Label">
            <property name="width_request">100</property>
            <property name="height_request">80</property>
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">Project Thoth
</property>
            <property name="angle">0.089999999999999997</property>
            <attributes>
              <attribute name="weight" value="bold"/>
            </attributes>
          </object>
          <packing>
            <property name="x">156</property>
            <property name="y">14</property>
          </packing>
        </child>
        <child>
          <object class="GtkEntry" id="user1">
            <property name="width_request">166</property>
            <property name="height_request">80</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
          </object>
          <packing>
            <property name="x">128</property>
            <property name="y">72</property>
          </packing>
        </child>
        <child>
          <object class="GtkLabel" id="label1">
            <property name="width_request">100</property>
            <property name="height_request">80</property>
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">Username: 
</property>
          </object>
          <packing>
            <property name="x">121</property>
            <property name="y">52</property>
          </packing>
        </child>
        <child>
          <object class="GtkEntry" id="pass">
            <property name="width_request">166</property>
            <property name="height_request">84</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
          </object>
          <packing>
            <property name="x">129</property>
            <property name="y">130</property>
          </packing>
        </child>
        <child>
          <object class="GtkLabel" id="label3">
            <property name="width_request">100</property>
            <property name="height_request">80</property>
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">Password:

</property>
          </object>
          <packing>
            <property name="x">117</property>
            <property name="y">123</property>
          </packing>
        </child>
        <child>
          <object class="GtkButton" id="button1">
            <property name="label" translatable="yes">Login</property>
            <property name="width_request">70</property>
            <property name="height_request">29</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">True</property>
            <property name="relief">half</property>
            <signal name="clicked" handler="on_login_clicked" swapped="no"/>
          </object>
          <packing>
            <property name="x">171</property>
            <property name="y">191</property>
          </packing>
        </child>
        <child>
          <object class="GtkLabel" id="label2">
            <property name="width_request">105</property>
            <property name="height_request">35</property>
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">save info login ?</property>
          </object>
          <packing>
            <property name="x">154</property>
            <property name="y">227</property>
          </packing>
        </child>
        <child>
          <object class="GtkSwitch" id="switch1">
            <property name="width_request">74</property>
            <property name="height_request">23</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
          </object>
          <packing>
            <property name="x">166</property>
            <property name="y">263</property>
          </packing>
        </child>
      </object>
    </child>
  </object>
</interface>

我还使用了以下标志进行编译

g++ -o "Project Thoth" main.cpp $(pkg-config --cflags --libs gtk+-3.0 gmodule-2.0 )

在此先感谢您的帮助。

Answer 1

该消息给出了一个很好的建议:使用 -rdynamic 编译(实际上是链接)，因此使用以下代码编译您的代码:

 g++ -rdynamic  -o Project_Thoth -Wall -g main.cpp \
     $(pkg-config --cflags --libs gtk+-3.0 gmodule-2.0 )

顺便说一句，我强烈建议您避免在可执行文件名称中使用空格。所以 Project_Thoth 不是 “Project Thoth”。此外，不要忘记询问警告(至少使用 -Wall，也许还可以添加 -Wextra)和调试信息(-g)，这非常有用，尤其是使用 gdb 调试器调试程序(或使用 valgrind 寻找内存泄漏)。

程序调试完成后，出于基准测试的目的，您可能会要求编译器进行优化(因此添加 -O2)。

顺便说一句，如果你真的想将 GTK 与 C++(不仅仅是 C)一起使用，请考虑 gtkmm .但是您可以使用纯 C99 编写您的 GTK 程序(因此没有 cout，而是 printf)。甚至可以考虑切换到 Qt (另一个小部件工具包，在 C++ 中)，如果 C++ 对您很重要。

如果使用 GTK(不是 gtkmm)在 C++ 中编码，最好将您的 GTK 相关代码声明为 extern "C" 所有。