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本节标题的含义是：如何查看一个thread的线程执行函数，

stackoverflow How to list the threads along with it's appropriate function in GDB.?

A :

You can use thread apply all bt command. It will print backtraces of all your threads. You will find thread function name inside each of these backtrace near the end and before clone system call.

A :

I press Ctrl+L to clear the screen buffer

set height 0
thread apply all bt

This will dump backtrace for all the threads but won't pause (because we set the window height to 0) if the list is long. I then copy/paste the output to a text editor for examination.

下面是我们的实践:

(gdb) info  threads 
  Id   Target Id         Frame 
  5    Thread 0x7f3a780ee700 (LWP 142466) "main" 0x00007f3a78d73cf2 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  4    Thread 0x7f3a778ed700 (LWP 142467) "main" 0x00007f3a790431ad in nanosleep () from /lib64/libc.so.6
  3    Thread 0x7f3a770ec700 (LWP 142468) "main" 0x00007f3a7907c923 in epoll_wait () from /lib64/libc.so.6
  2    Thread 0x7f3a768eb700 (LWP 142469) "main" 0x00007f3a7907c923 in epoll_wait () from /lib64/libc.so.6
* 1    Thread 0x7f3a7a334780 (LWP 142465) "main" 0x00007f3a790431ad in nanosleep () from /lib64/libc.so.6
(gdb) thread apply all bt

Thread 5 (Thread 0x7f3a780ee700 (LWP 142466)):
#0  0x00007f3a78d73cf2 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00007f3a787495e2 in __gthread_cond_timedwait (__abs_timeout=0x7f3a780edd80, __mutex=<optimized out>, __cond=0x212a388)
    at /usr/include/c++/4.8.2/x86_64-redhat-linux/bits/gthr-default.h:871
#2  __wait_until_impl<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x212a388)
    at /usr/include/c++/4.8.2/condition_variable:160
#3  wait_until<std::chrono::duration<long, std::ratio<1l, 1000000000l> > > (__atime=..., __lock=..., this=0x212a388)
    at /usr/include/c++/4.8.2/condition_variable:100
#4  wait_until<std::chrono::_V2::system_clock, std::chrono::duration<long int, std::ratio<1l, 1000000000l> >, CEvent::Wait(int64_t)::__lambda0> (
    __p=..., __atime=..., __lock=..., this=0x212a388) at /usr/include/c++/4.8.2/condition_variable:123
#5  wait_for<long int, std::ratio<1l, 1000l>, CEvent::Wait(int64_t)::__lambda0> (__p=..., __rtime=..., __lock=..., this=0x212a388)
    at /usr/include/c++/4.8.2/condition_variable:139
#6  CEvent::Wait (this=0x212a360, dwMillsSecond=dwMillsSecond@entry=100) at ../../plugins/logproxy/event.cpp:44
#7  0x00007f3a787453da in Pop (iTimeOut=100, this=0x212a290) at ../../plugins/logproxy/log_queue.h:92
#8  CLogProxyImpl::Run (this=<optimized out>) at ../../plugins/logproxy/log_proxy_impl.cpp:367
#9  0x00007f3a799142b0 in ?? () from /lib64/libstdc++.so.6
#10 0x00007f3a78d6fe25 in start_thread () from /lib64/libpthread.so.0
#11 0x00007f3a7907c34d in clone () from /lib64/libc.so.6

Thread 4 (Thread 0x7f3a778ed700 (LWP 142467)):
#0  0x00007f3a790431ad in nanosleep () from /lib64/libc.so.6
#1  0x00007f3a79073ec4 in usleep () from /lib64/libc.so.6
#2  0x00007f3a78740470 in sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/4.8.2/thread:281
#3  CCheckConnThread::Run (this=0x2161040) at ../../utilities/tcp/tcp_factory.cpp:608
#4  0x00007f3a799142b0 in ?? () from /lib64/libstdc++.so.6
#5  0x00007f3a78d6fe25 in start_thread () from /lib64/libpthread.so.0
#6  0x00007f3a7907c34d in clone () from /lib64/libc.so.6

Thread 3 (Thread 0x7f3a770ec700 (LWP 142468)):
#0  0x00007f3a7907c923 in epoll_wait () from /lib64/libc.so.6
#1  0x00007f3a78740b4a in CTcpSendThread::Run (this=0x2160f48) at ../../utilities/tcp/tcp_factory.cpp:228
#2  0x00007f3a799142b0 in ?? () from /lib64/libstdc++.so.6
#3  0x00007f3a78d6fe25 in start_thread () from /lib64/libpthread.so.0
#4  0x00007f3a7907c34d in clone () from /lib64/libc.so.6
---Type <return> to continue, or q <return> to quit---

Thread 2 (Thread 0x7f3a768eb700 (LWP 142469)):
#0  0x00007f3a7907c923 in epoll_wait () from /lib64/libc.so.6
#1  0x00007f3a7874094a in CTcpRecvThread::Run (this=0x2160fc8) at ../../utilities/tcp/tcp_factory.cpp:261
#2  0x00007f3a799142b0 in ?? () from /lib64/libstdc++.so.6
#3  0x00007f3a78d6fe25 in start_thread () from /lib64/libpthread.so.0
#4  0x00007f3a7907c34d in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f3a7a334780 (LWP 142465)):
#0  0x00007f3a790431ad in nanosleep () from /lib64/libc.so.6
#1  0x00007f3a79073ec4 in usleep () from /lib64/libc.so.6
#2  0x0000000000406189 in sleep_for<long, std::ratio<1l, 1000l> > (__rtime=...) at /usr/include/c++/4.8.2/thread:281
#3  CMyApp::Run (this=this@entry=0x7ffcb3fa4b50) at ../HA-test-1/app.h:251
#4  0x00000000004032ac in main () at main.cpp:43

从上面的输出可以看出：

  • Thread 1是main thread，它不是由clone system call创建的，其他thread都是由clone system call创建的