Debugging with GDB (8) 4.10 Debugging Programs with Multiple Threads

提供以下功能：

automatic notification of new threads
‘thread threadno’, a command to switch among threads
‘info threads’, a command to inquire about existing threads
‘thread apply [threadno] [all] args’, a command to apply a command to a list of threads
thread-specific breakpoints
‘set print thread-events’, which controls printing of messages on thread start and exit.
‘set libthread-db-search-path path’, which lets the user specify which libthread_db to use if the default choice isn't compatible with the program.