我有一个多线程程序,我试图调试。当我在GDB中运行info thread
时,我得到以下内容:
(gdb) info thread
Id Target Id Frame
8 Thread 0x7fffe77fd700 (LWP 17425) "SocketWriter" 0x00007ffff7bc9b2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
7 Thread 0x7fffe73fc700 (LWP 17426) "SocketWriter" 0x00007ffff7bc9b2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
6 Thread 0x7fffe7fff700 (LWP 17423) "SocketReader" 0x00007ffff7bcc66d in read () from /usr/lib/libpthread.so.0
5 Thread 0x7fffe7bfe700 (LWP 17424) "SocketReader" 0x00007ffff7bcc66d in read () from /usr/lib/libpthread.so.0
* 4 Thread 0x7ffff4810700 (LWP 17422) "unittest" 0x00007ffff7bcc38c in __lll_lock_wait () from /usr/lib/libpthread.so.0
3 Thread 0x7ffff4c11700 (LWP 17421) "receiver" 0x00007ffff7bcc38c in __lll_lock_wait () from /usr/lib/libpthread.so.0
2 Thread 0x7ffff5a3b700 (LWP 17420) "unittest" 0x00007ffff634e553 in select () from /usr/lib/libc.so.6
1 Thread 0x7ffff7fc9780 (LWP 17419) "unittest" 0x00007ffff7bc9b2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
如果我能让GDB显示线程之间的父/子关系,那就太好了,就像下面这样:
(gdb) info thread
Id Target Id Frame
1 Thread 0x7ffff7fc9780 (LWP 17419) "unittest" 0x00007ffff7bc9b2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
3 Thread 0x7ffff4c11700 (LWP 17421) "receiver" 0x00007ffff7bcc38c in __lll_lock_wait () from /usr/lib/libpthread.so.0
8 Thread 0x7fffe77fd700 (LWP 17425) "SocketWriter" 0x00007ffff7bc9b2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
6 Thread 0x7fffe7fff700 (LWP 17423) "SocketReader" 0x00007ffff7bcc66d in read () from /usr/lib/libpthread.so.0
2 Thread 0x7ffff5a3b700 (LWP 17420) "unittest" 0x00007ffff634e553 in select () from /usr/lib/libc.so.6
5 Thread 0x7fffe7bfe700 (LWP 17424) "SocketReader" 0x00007ffff7bcc66d in read () from /usr/lib/libpthread.so.0
* 4 Thread 0x7ffff4810700 (LWP 17422) "unittest" 0x00007ffff7bcc38c in __lll_lock_wait () from /usr/lib/libpthread.so.0
7 Thread 0x7fffe73fc700 (LWP 17426) "SocketWriter" 0x00007ffff7bc9b2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0
例如,线程3是线程8、6和2的父线程,而线程1是所有线程的父线程。
这样的功能存在吗?
gdb不打印此信息,因为它不存在于您的程序中——一旦线程被创建,gdb就无法发现它。
可能有两种方法。
首先,您可以在线程创建函数上设置一个断点并记录该信息。这很容易从Python中完成。然后你可以写一个新的命令,同样是在Python中,以你喜欢的方式格式化输出。
这种方法的问题是,如果您"附加"到正在运行的程序,它将不起作用。要获取这些信息就太晚了。
另一种方法是,如果您的程序中有描述层次结构的额外可用信息。然后,您可以在Python中编写一个新命令,提取这些信息以显示您喜欢的内容。