1 // gdb non-stop mode demo
2 // build instruction: g++ -g -o nonstop nonstop.cpp -lboost_thread
3
4 #include <iostream>
5 #include <boost/thread/thread.hpp>
6
7 struct op
8 {
9 op(int id): m_id(id) {}
10
11 void operator()()
12 {
13 std::cout << m_id << " begin" << std::endl;
14 std::cout << m_id << " end" << std::endl;
15 }
16
17 int m_id;
18 };
19
20 int main(int argc, char ** argv)
21 {
22 boost::thread t1(op(1)), t2(op(2)), t3(op(3));
23 t1.join(); t2.join(); t3.join();
24 return 0;
25 }
26
2. 把一下3行添加到~/.gdbinit来打开non-stop模式
set target-async 1
set pagination off
set non-stop on
3. 启动gdb,设断点,运行.可以看到主线程1是running,3个子线程都断在断点上,而不是只有一个子线程断在断点上.
~/devroot/nonstop$ gdb ./nonstop
GNU gdb (GDB) 7.0-ubuntu
Reading symbols from /home/frankwu/devroot/nonstop/nonstop...done.
(gdb) break 14
Breakpoint 1 at 0x402058: file nonstop.cpp, line 14.
(gdb) break 24
Breakpoint 3 at 0x401805: file nonstop.cpp, line 24.
(gdb) run
Starting program: /home/frankwu/devroot/nonstop/nonstop
[Thread debugging using libthread_db enabled]
[New Thread 0x7ffff6c89910 (LWP 2762)]
[New Thread 0x7ffff6488910 (LWP 2763)]
1 begin
Breakpoint 1, op::operator() (this=0x605118) at nonstop.cpp:14
14 std::cout << m_id << " end" << std::endl;
2 begin
Breakpoint 1, op::operator() (this=0x605388) at nonstop.cpp:14
14 std::cout << m_id << " end" << std::endl;
[New Thread 0x7ffff5c87910 (LWP 2764)]
3 begin
Breakpoint 1, op::operator() (this=0x605618) at nonstop.cpp:14
14 std::cout << m_id << " end" << std::endl;
(gdb) info threads
4 Thread 0x7ffff5c87910 (LWP 2764) op::operator() (this=0x605618) at nonstop.cpp:14
3 Thread 0x7ffff6488910 (LWP 2763) op::operator() (this=0x605388) at nonstop.cpp:14
2 Thread 0x7ffff6c89910 (LWP 2762) op::operator() (this=0x605118) at nonstop.cpp:14
* 1 Thread 0x7ffff7fe3710 (LWP 2759) (running)
4. 让线程3继续运行,注意我顾意把主线程1也continue,这是我发现的workaround,否则gdb不能切回thread 1.
(gdb) thread apply 3 1 continue
Thread 3 (Thread 0x7ffff6488910 (LWP 2763)):
Continuing.
Thread 1 (Thread 0x7ffff7fe3710 (LWP 2759)):
Continuing.
Cannot execute this command while the selected thread is running.
2 end
[Thread 0x7ffff6488910 (LWP 2763) exited]
warning: Unknown thread 3.
Thread 1 (Thread 0x7ffff7fe3710 (LWP 2759)):
Continuing.
Cannot execute this command while the selected thread is running.
(gdb) info threads
4 Thread 0x7ffff5c87910 (LWP 2764) op::operator() (this=0x605618) at nonstop.cpp:14
2 Thread 0x7ffff6c89910 (LWP 2762) op::operator() (this=0x605118) at nonstop.cpp:14
* 1 Thread 0x7ffff7fe3710 (LWP 2759) (running)
5. 让另外两个线程继续运行而结束,主线程断在第24行,最后结束.
(gdb) thread apply 4 2 1 continue
Thread 4 (Thread 0x7ffff5c87910 (LWP 2764)):
Continuing.
Thread 2 (Thread 0x7ffff6c89910 (LWP 2762)):
Continuing.
Thread 1 (Thread 0x7ffff7fe3710 (LWP 2759)):
Continuing.
Cannot execute this command while the selected thread is running.
3 end
1 end
[Thread 0x7ffff5c87910 (LWP 2764) exited]
[Thread 0x7ffff6c89910 (LWP 2762) exited]
Breakpoint 3, main (argc=1, argv=0x7fffffffe348) at nonstop.cpp:24
24 return 0;
(gdb) continue
Thread 1 (Thread 0x7ffff7fe3710 (LWP 2759)):
Continuing.
Program exited normally.
参考资料
Debugging with GDB
Reverse Debugging, Multi-Process and Non-Stop Debugging Come to the CDT
GDB的non-stop模式
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