更改 gtkmm 小部件的标签时出现零星段错误
sporadic segfaults when changing label of gtkmm widget
嗨，
我有一个 gtkmm 应用程序，它执行一些异步网络请求，向服务器询问 gtk-widgets 的其他属性。
这意味着，例如，应用程序应该能够更改小部件的标签。
在此示例中，我创建了一个基于 Gtk::ToggleButton 的新小部件。
但我发现有时 gtkmm 应用程序会因段错误而崩溃。当使用 gdb 调试时，我总是得到设置标签的行。
为了更好地理解，我创建了一个 MWE，它在循环中进行标签更改，以模拟大量异步调用：
#include <boost/asio.hpp>
#include <boost/asio/steady_timer.hpp>
#include <iostream>
#include <thread>
#include <mutex>
#include <gtkmm/application.h>
#include <gtkmm/window.h>
#include <gtkmm/togglebutton.h>
class led_label_t : public Gtk::ToggleButton {
public:
using value_list_t = std::vector<Glib::ustring>;
using lock_t = std::lock_guard<std::mutex>;
led_label_t(Glib::ustring label = "<no data>", bool mnemonic = false)
: Gtk::ToggleButton(std::move(label), std::move(mnemonic)),
_values{"SEL1", "SEL2"} {}
protected:
virtual void on_toggled(void) override {
std::cout << "Clicked Button." << std::endl;
lock_t lock(_mtx);
value_changed(_values[get_active()]);
}
virtual void value_changed(Glib::ustring& value) {
std::string path;
if (get_active()) {
path =
"/usr/share/icons/Adwaita/16x16/emblems/emblem-important.png";
} else {
path = "/usr/share/icons/Adwaita/16x16/emblems/emblem-default.png";
}
remove(); // remove previous label
std::cout << "Changed Label of led_label: "
<< ", value: " << value << std::endl;
add_pixlabel(path, value);
}
private:
mutable std::mutex _mtx;
value_list_t _values;
};
int main(void) {
auto app = Gtk::Application::create();
Gtk::Window window;
window.set_default_size(200, 200);
led_label_t inst{};
inst.show();
window.add(inst);
auto f = [&inst, &window]() {
using namespace std::chrono_literals;
boost::asio::io_service io;
{ //wait for startup
boost::asio::steady_timer t{io, 100ms};
t.wait();
}
bool toggle = true;
for (auto i = 0; i < 2000; i++) {
std::cout << "i=" << i << std::endl;
//wait until next simulated button click
boost::asio::steady_timer t{io, 1ms};
t.wait();
inst.set_active(toggle);
toggle = !toggle;
}
};
std::thread c1(f);
std::thread w([&app, &window]() { app->run(window); });
c1.join();
window.hide();
w.join();
return EXIT_SUCCESS;
}
要编译此示例，我使用以下命令：
g++ main.cpp -o main `pkg-config --cflags --libs gtkmm-3.0` -Wall -pedantic -Wextra -Werror -Wcast-qual -Wcast-align -Wconversion -fdiagnostics-color=auto -g -O0 -std=c++14 -lboost_system -pthread
我正在使用 GCC 4.9.2 和 libgtkmm-3.14（都是标准的 debian jessie）
我得到的段错误如下：
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffe7fff700 (LWP 7888)]
0x00007ffff6288743 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
(gdb) bt
#0 0x00007ffff6288743 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#1 0x00007ffff6288838 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#2 0x00007ffff6267ce9 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#3 0x00007ffff627241b in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#4 0x00007ffff63a1601 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#5 0x00007ffff63a154c in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#6 0x00007ffff63a26b8 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#7 0x00007ffff644d5ff in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#8 0x00007ffff644d9b7 in gtk_widget_realize ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#9 0x00007ffff644dbe8 in gtk_widget_map ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#10 0x00007ffff621c387 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#11 0x00007ffff626270f in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#12 0x00007ffff46bf474 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007ffff46d9087 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#14 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#15 0x00007ffff644db99 in gtk_widget_map ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#16 0x00007ffff64506d8 in gtk_widget_set_parent ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#17 0x00007ffff6217a9b in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#18 0x00007ffff79a44eb in Gtk::Container_Class::add_callback(_GtkContainer*, _GtkWidget*) () from /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
#19 0x00007ffff46c253b in g_cclosure_marshal_VOID__OBJECTv ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#20 0x00007ffff46bf474 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#21 0x00007ffff46d9087 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#22 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#23 0x00007ffff6261aa5 in gtk_container_add ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#24 0x000000000040b0b5 in led_label_t::value_changed (this=0x7fffffffe2a0,
value=...) at main.cpp:38
#25 0x000000000040afb1 in led_label_t::on_toggled (this=0x7fffffffe2a0)
at main.cpp:24
#26 0x00007ffff7a18af0 in Gtk::ToggleButton_Class::toggled_callback(_GtkToggleButton*) () from /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
#27 0x00007ffff46bf245 in g_closure_invoke ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#28 0x00007ffff46d083b in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#29 0x00007ffff46d9778 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#30 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#31 0x00007ffff63ecb4d in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#32 0x00007ffff798a4a0 in Gtk::Button_Class::clicked_callback(_GtkButton*) ()
from /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
#33 0x00007ffff46bf474 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#34 0x00007ffff46d9087 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#35 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#36 0x00007ffff63ec936 in gtk_toggle_button_set_active ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#37 0x0000000000405e12 in <lambda()>::operator()(void) const (
__closure=0x74f4f8) at main.cpp:73
#38 0x000000000040811a in std::_Bind_simple<main()::<lambda()>()>::_M_invoke<>(std::_Index_tuple<>) (this=0x74f4f8) at /usr/include/c++/4.9/functional:1700
#39 0x0000000000407fa9 in std::_Bind_simple<main()::<lambda()>()>::operator()(void) (this=0x74f4f8) at /usr/include/c++/4.9/functional:1688
#40 0x0000000000407e9e in std::thread::_Impl<std::_Bind_simple<main()::<lambda()>()> >::_M_run(void) (this=0x74f4e0) at /usr/include/c++/4.9/thread:115
#41 0x00007ffff3f47970 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#42 0x00007ffff37650a4 in start_thread (arg=0x7fffe7fff700)
at pthread_create.c:309
#43 0x00007ffff349a04d in clone ()
at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
也许有趣的是
#24: 0x000000000040b0b5 in led_label_t::value_changed (this=0x7fffffffe2a0,
value=...) at main.cpp:38)
这是 add_pixlabel(path, value);被调用。
我做错了什么？
注意：
我发现，这种段错误并不总是出现，在我的台式机上，每 10 次调用就会出现一次错误。 （英特尔 i7-3xxx）
在我的笔记本电脑上，几乎每次调用时都会出现错误 (Intel i5-3xxx)
从多个线程访问和更改 UI 组件总是很棘手。 UIs 需要快速响应用户输入，因此他们不能等待后台任务完成。因此 UI 组件很少受到互斥锁或其他同步的保护。你写，它发生了。除非遇到其他事情。
如果您从两个线程写入...糟糕。
当另一个线程读取时，您正在写入一半...糟糕。
例如，当触发屏幕刷新时，线程 4 正在通过将新字符串写入标签的方式进行部分处理。如果标签的后端是 c 风格的字符串，则终止 NULL 可能已被覆盖，并且标签写入从末尾运行到错误的 RAM 中。
各种各样的事情都可能出错，有些会幸存下来，或者更糟的是，看起来像。最好将所有 UI 管理都放在一个线程中，让其他线程对 UI 线程的更新进行排队。首先查看 Model View Controller，然后根据需要尝试相关模式。
根据@user4581301的回答，我现在找到了解决办法。他是对的，gtkmm 不支持多线程。 （更准确地说，libsigc++ 和 sigc::trackable 不是线程安全的）
However, care is required when writing programs based on gtkmm using
multiple threads of execution, arising from the fact that libsigc++,
and in particular sigc::trackable, are not thread-safe.
Quote from gtkmm documentation.
因此我使用 Glib::Dispatcher 在 window.
的 gtkmm-Main-Loop 上下文中执行 set_label() - 方法
这是代码，它在我的机器上不再出现段错误（即使重试多次）
#include <boost/asio.hpp>
#include <boost/asio/steady_timer.hpp>
#include <cassert>
#include <iostream>
#include <thread>
#include <mutex>
#include <gtkmm/application.h>
#include <gtkmm/window.h>
#include <gtkmm/togglebutton.h>
#include <glibmm/dispatcher.h>
#define LOG() \
std::cout << (std::chrono::system_clock::now() - start).count() << " " \
<< std::this_thread::get_id() << ": "
auto start = std::chrono::system_clock::now();
class led_label_t : public Gtk::ToggleButton {
public:
using value_list_t = std::vector<Glib::ustring>;
using lock_t = std::lock_guard<std::mutex>;
using action_queue_t = std::vector<Glib::ustring>;
led_label_t(Glib::ustring label = "<no data>", bool mnemonic = false)
: Gtk::ToggleButton(std::move(label), std::move(mnemonic)),
_values{"SEL1", "SEL2"} {}
void set_dispatcher(Glib::Dispatcher* dp) {
_dp = dp;
_dp->connect([this](void) { dispatcher_task(); });
}
protected:
virtual void on_toggled(void) override {
LOG() << "Clicked Button." << std::endl;
{
lock_t lock(_action_mtx);
auto value = _values[get_active()];
_action_queue.push_back({value});
LOG() << "Added label into queue " << value << std::endl;
if (_action_queue.size() > 1) {
return;
}
}
_dp->emit();
}
void dispatcher_task(void) {
Glib::ustring label;
for (;;) {
{
lock_t lock(_action_mtx);
if (_action_queue.size() == 0) {
return;
}
label = *_action_queue.begin();
_action_queue.erase(_action_queue.begin());
}
set_label(label);
LOG() << "Set the label " << label << std::endl;
}
}
private:
mutable std::mutex _action_mtx;
action_queue_t _action_queue;
value_list_t _values;
Glib::Dispatcher* _dp;
};
int main(void) {
auto app = Gtk::Application::create();
Gtk::Window window;
window.set_default_size(200, 200);
led_label_t inst{};
inst.show();
window.add(inst);
auto f = [&inst, &window]() {
using namespace std::chrono_literals;
boost::asio::io_service io;
{ // wait for startup
boost::asio::steady_timer t{io, 100ms};
t.wait();
}
bool toggle = true;
for (auto i = 0; i < 200000; i++) {
// wait until next simulated button click
boost::asio::steady_timer t{io, 250us};
t.wait();
LOG() << "i=" << i << std::endl;
inst.set_active(toggle);
toggle = !toggle;
LOG() << "finished" << std::endl;
}
};
std::thread c1(f);
std::thread w([&app, &window, &inst]() {
Glib::Dispatcher dp;
inst.set_dispatcher(&dp);
app->run(window);
});
c1.join();
window.hide();
w.join();
return EXIT_SUCCESS;
}
嗨， 我有一个 gtkmm 应用程序，它执行一些异步网络请求，向服务器询问 gtk-widgets 的其他属性。 这意味着，例如，应用程序应该能够更改小部件的标签。
在此示例中，我创建了一个基于 Gtk::ToggleButton 的新小部件。
但我发现有时 gtkmm 应用程序会因段错误而崩溃。当使用 gdb 调试时，我总是得到设置标签的行。
为了更好地理解，我创建了一个 MWE，它在循环中进行标签更改，以模拟大量异步调用：
#include <boost/asio.hpp>
#include <boost/asio/steady_timer.hpp>
#include <iostream>
#include <thread>
#include <mutex>
#include <gtkmm/application.h>
#include <gtkmm/window.h>
#include <gtkmm/togglebutton.h>
class led_label_t : public Gtk::ToggleButton {
public:
using value_list_t = std::vector<Glib::ustring>;
using lock_t = std::lock_guard<std::mutex>;
led_label_t(Glib::ustring label = "<no data>", bool mnemonic = false)
: Gtk::ToggleButton(std::move(label), std::move(mnemonic)),
_values{"SEL1", "SEL2"} {}
protected:
virtual void on_toggled(void) override {
std::cout << "Clicked Button." << std::endl;
lock_t lock(_mtx);
value_changed(_values[get_active()]);
}
virtual void value_changed(Glib::ustring& value) {
std::string path;
if (get_active()) {
path =
"/usr/share/icons/Adwaita/16x16/emblems/emblem-important.png";
} else {
path = "/usr/share/icons/Adwaita/16x16/emblems/emblem-default.png";
}
remove(); // remove previous label
std::cout << "Changed Label of led_label: "
<< ", value: " << value << std::endl;
add_pixlabel(path, value);
}
private:
mutable std::mutex _mtx;
value_list_t _values;
};
int main(void) {
auto app = Gtk::Application::create();
Gtk::Window window;
window.set_default_size(200, 200);
led_label_t inst{};
inst.show();
window.add(inst);
auto f = [&inst, &window]() {
using namespace std::chrono_literals;
boost::asio::io_service io;
{ //wait for startup
boost::asio::steady_timer t{io, 100ms};
t.wait();
}
bool toggle = true;
for (auto i = 0; i < 2000; i++) {
std::cout << "i=" << i << std::endl;
//wait until next simulated button click
boost::asio::steady_timer t{io, 1ms};
t.wait();
inst.set_active(toggle);
toggle = !toggle;
}
};
std::thread c1(f);
std::thread w([&app, &window]() { app->run(window); });
c1.join();
window.hide();
w.join();
return EXIT_SUCCESS;
}
要编译此示例，我使用以下命令：
g++ main.cpp -o main `pkg-config --cflags --libs gtkmm-3.0` -Wall -pedantic -Wextra -Werror -Wcast-qual -Wcast-align -Wconversion -fdiagnostics-color=auto -g -O0 -std=c++14 -lboost_system -pthread
我正在使用 GCC 4.9.2 和 libgtkmm-3.14（都是标准的 debian jessie）
我得到的段错误如下：
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffe7fff700 (LWP 7888)]
0x00007ffff6288743 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
(gdb) bt
#0 0x00007ffff6288743 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#1 0x00007ffff6288838 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#2 0x00007ffff6267ce9 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#3 0x00007ffff627241b in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#4 0x00007ffff63a1601 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#5 0x00007ffff63a154c in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#6 0x00007ffff63a26b8 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#7 0x00007ffff644d5ff in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#8 0x00007ffff644d9b7 in gtk_widget_realize ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#9 0x00007ffff644dbe8 in gtk_widget_map ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#10 0x00007ffff621c387 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#11 0x00007ffff626270f in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#12 0x00007ffff46bf474 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007ffff46d9087 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#14 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#15 0x00007ffff644db99 in gtk_widget_map ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#16 0x00007ffff64506d8 in gtk_widget_set_parent ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#17 0x00007ffff6217a9b in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#18 0x00007ffff79a44eb in Gtk::Container_Class::add_callback(_GtkContainer*, _GtkWidget*) () from /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
#19 0x00007ffff46c253b in g_cclosure_marshal_VOID__OBJECTv ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#20 0x00007ffff46bf474 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#21 0x00007ffff46d9087 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#22 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#23 0x00007ffff6261aa5 in gtk_container_add ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#24 0x000000000040b0b5 in led_label_t::value_changed (this=0x7fffffffe2a0,
value=...) at main.cpp:38
#25 0x000000000040afb1 in led_label_t::on_toggled (this=0x7fffffffe2a0)
at main.cpp:24
#26 0x00007ffff7a18af0 in Gtk::ToggleButton_Class::toggled_callback(_GtkToggleButton*) () from /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
#27 0x00007ffff46bf245 in g_closure_invoke ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#28 0x00007ffff46d083b in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#29 0x00007ffff46d9778 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#30 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#31 0x00007ffff63ecb4d in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#32 0x00007ffff798a4a0 in Gtk::Button_Class::clicked_callback(_GtkButton*) ()
from /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
#33 0x00007ffff46bf474 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#34 0x00007ffff46d9087 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#35 0x00007ffff46d99df in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#36 0x00007ffff63ec936 in gtk_toggle_button_set_active ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#37 0x0000000000405e12 in <lambda()>::operator()(void) const (
__closure=0x74f4f8) at main.cpp:73
#38 0x000000000040811a in std::_Bind_simple<main()::<lambda()>()>::_M_invoke<>(std::_Index_tuple<>) (this=0x74f4f8) at /usr/include/c++/4.9/functional:1700
#39 0x0000000000407fa9 in std::_Bind_simple<main()::<lambda()>()>::operator()(void) (this=0x74f4f8) at /usr/include/c++/4.9/functional:1688
#40 0x0000000000407e9e in std::thread::_Impl<std::_Bind_simple<main()::<lambda()>()> >::_M_run(void) (this=0x74f4e0) at /usr/include/c++/4.9/thread:115
#41 0x00007ffff3f47970 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#42 0x00007ffff37650a4 in start_thread (arg=0x7fffe7fff700)
at pthread_create.c:309
#43 0x00007ffff349a04d in clone ()
at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
也许有趣的是
#24: 0x000000000040b0b5 in led_label_t::value_changed (this=0x7fffffffe2a0,
value=...) at main.cpp:38)
这是 add_pixlabel(path, value);被调用。
我做错了什么？
注意： 我发现，这种段错误并不总是出现，在我的台式机上，每 10 次调用就会出现一次错误。 （英特尔 i7-3xxx） 在我的笔记本电脑上，几乎每次调用时都会出现错误 (Intel i5-3xxx)
从多个线程访问和更改 UI 组件总是很棘手。 UIs 需要快速响应用户输入，因此他们不能等待后台任务完成。因此 UI 组件很少受到互斥锁或其他同步的保护。你写，它发生了。除非遇到其他事情。
如果您从两个线程写入...糟糕。
当另一个线程读取时，您正在写入一半...糟糕。
例如，当触发屏幕刷新时，线程 4 正在通过将新字符串写入标签的方式进行部分处理。如果标签的后端是 c 风格的字符串，则终止 NULL 可能已被覆盖，并且标签写入从末尾运行到错误的 RAM 中。
各种各样的事情都可能出错，有些会幸存下来，或者更糟的是，看起来像。最好将所有 UI 管理都放在一个线程中，让其他线程对 UI 线程的更新进行排队。首先查看 Model View Controller，然后根据需要尝试相关模式。
根据@user4581301的回答，我现在找到了解决办法。他是对的，gtkmm 不支持多线程。 （更准确地说，libsigc++ 和 sigc::trackable 不是线程安全的）
However, care is required when writing programs based on gtkmm using multiple threads of execution, arising from the fact that libsigc++, and in particular sigc::trackable, are not thread-safe.
Quote from gtkmm documentation.
因此我使用 Glib::Dispatcher 在 window.
的 gtkmm-Main-Loop 上下文中执行 set_label() - 方法这是代码，它在我的机器上不再出现段错误（即使重试多次）
#include <boost/asio.hpp>
#include <boost/asio/steady_timer.hpp>
#include <cassert>
#include <iostream>
#include <thread>
#include <mutex>
#include <gtkmm/application.h>
#include <gtkmm/window.h>
#include <gtkmm/togglebutton.h>
#include <glibmm/dispatcher.h>
#define LOG() \
std::cout << (std::chrono::system_clock::now() - start).count() << " " \
<< std::this_thread::get_id() << ": "
auto start = std::chrono::system_clock::now();
class led_label_t : public Gtk::ToggleButton {
public:
using value_list_t = std::vector<Glib::ustring>;
using lock_t = std::lock_guard<std::mutex>;
using action_queue_t = std::vector<Glib::ustring>;
led_label_t(Glib::ustring label = "<no data>", bool mnemonic = false)
: Gtk::ToggleButton(std::move(label), std::move(mnemonic)),
_values{"SEL1", "SEL2"} {}
void set_dispatcher(Glib::Dispatcher* dp) {
_dp = dp;
_dp->connect([this](void) { dispatcher_task(); });
}
protected:
virtual void on_toggled(void) override {
LOG() << "Clicked Button." << std::endl;
{
lock_t lock(_action_mtx);
auto value = _values[get_active()];
_action_queue.push_back({value});
LOG() << "Added label into queue " << value << std::endl;
if (_action_queue.size() > 1) {
return;
}
}
_dp->emit();
}
void dispatcher_task(void) {
Glib::ustring label;
for (;;) {
{
lock_t lock(_action_mtx);
if (_action_queue.size() == 0) {
return;
}
label = *_action_queue.begin();
_action_queue.erase(_action_queue.begin());
}
set_label(label);
LOG() << "Set the label " << label << std::endl;
}
}
private:
mutable std::mutex _action_mtx;
action_queue_t _action_queue;
value_list_t _values;
Glib::Dispatcher* _dp;
};
int main(void) {
auto app = Gtk::Application::create();
Gtk::Window window;
window.set_default_size(200, 200);
led_label_t inst{};
inst.show();
window.add(inst);
auto f = [&inst, &window]() {
using namespace std::chrono_literals;
boost::asio::io_service io;
{ // wait for startup
boost::asio::steady_timer t{io, 100ms};
t.wait();
}
bool toggle = true;
for (auto i = 0; i < 200000; i++) {
// wait until next simulated button click
boost::asio::steady_timer t{io, 250us};
t.wait();
LOG() << "i=" << i << std::endl;
inst.set_active(toggle);
toggle = !toggle;
LOG() << "finished" << std::endl;
}
};
std::thread c1(f);
std::thread w([&app, &window, &inst]() {
Glib::Dispatcher dp;
inst.set_dispatcher(&dp);
app->run(window);
});
c1.join();
window.hide();
w.join();
return EXIT_SUCCESS;
}