c++ - 为什么信号连接会使 SocketClient 对象失效？

Question

我正在尝试通过 giomm 与 Gio 的 SocketClient 类建立 TCP / TLS 连接。

一切都很好，直到我SocketClient::event_signal ()用sigc::ptr_fun ().

这是演示问题的精简示例代码：

#include <giomm/error.h>
#include <giomm/init.h>
#include <giomm/networkaddress.h>
#include <giomm/socketclient.h>
#include <glibmm/main.h>
#include <iostream>

void socket_client_event (Gio::SocketClientEvent event,
              const Glib::RefPtr<Gio::SocketConnectable> &connectable,
              const Glib::RefPtr<Gio::IOStream> &connection) {
}

int main () {
  auto loop = Glib::MainLoop::create ();
  Gio::init ();
  auto network_address = Gio::NetworkAddress::create ("www.example.org", 437);
  auto socket_client = Gio::SocketClient::create ();
  socket_client->set_tls (true);
  socket_client->signal_event ().connect (sigc::ptr_fun (&socket_client_event));
  Glib::RefPtr<Gio::SocketConnection> socket_connection;
  try {
    socket_connection = socket_client->connect (network_address);
  }
  catch (const Gio::TlsError &e) {
    std::cerr << e.what (). c_str () << std::endl;
    return 1;
  }
  catch (const Gio::Error &e) {
    std::cerr << e.what (). c_str () << std::endl;
    return 1;
  }

  loop->run ();
}

当该connect ()方法被调用时，我得到这个控制台输出：

(process:9046): GLib-GIO-CRITICAL **: g_socket_connection_connect: assertion 'G_IS_SOCKET_CONNECTION (connection)' failed

(process:9046): GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

(process:9046): GLib-GObject-CRITICAL **: g_object_get_qdata: assertion 'G_IS_OBJECT (object)' failed

(process:9046): GLib-GObject-CRITICAL **: g_object_get_qdata: assertion 'G_IS_OBJECT (object)' failed

然后一个分段错误使程序死亡。

我已经打开 G_DEBUG=all 并在第一个错误处停止，但根据回溯，这是connect ()方法内部的某个地方。

奇怪的是，注释掉连接信号处理程序的源代码行可以解决问题。

那么在这里连接信号时我做错了什么？为什么socket客户端连接后无效？

Answer 1

glibmm或 gio 中的引用计数似乎存在错误。

如果我在问题消失的情况下手动引用对象：

void socket_client_event (Gio::SocketClientEvent event,
              const Glib::RefPtr<Gio::SocketConnectable> &connectable,
              const Glib::RefPtr<Gio::IOStream> &connection) {
  // Workaround for reference counting problems
  if (connectable) {
    connectable->reference ();
  }
  if (connection) {
    connection->reference ();
  }
}