http://blog.csdn.net/pbymw8iwm/article/details/7876797 2012 1. 默认设置下,在调试多进程程序时GDB只会调试主进程。但是GDB(>V7.0)支持多进程的分别以及同时调试,换句话说,GDB可以同时调试多个程序。只需要设置follow-fork-mode(默认值:parent)和detach-on-fork(默认值:on)即可。parent
child parent child 2. GDB默认支持调试多线程,跟主线程,子线程block在create thread。 例程: #include <stdio.h>
输出:#include <pthread.h> void processA(); void processB(); void * processAworker(void *arg); int main(int argc, const char *argv[]) void processA() void * processAworker(void *arg) void processB() [cnwuwil@centos c-lab]$ ./test
ProcessA: 802 step1
ProcessB: 803 step1 ProcessB: 803 step2 ProcessB: 803 step3 ProcessA: 802 thread 3077555904 step2 ProcessA: 802 thread 3077555904 step3 ProcessA: 802 thread 3077553008 step2 ProcessA: 802 thread 3077553008 step3 调试: 1. 调试主进程,block子进程。 (gdb) set detach-on-fork off
2. 切换到子进程:(gdb) show detach-on-fork Whether gdb will detach the child of a fork is off. (gdb) catch fork Catchpoint 1 (fork) (gdb) r [Thread debugging using libthread_db enabled] Catchpoint 1 (forked process 3475), 0x00110424 in __kernel_vsyscall () Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.47.el6.i686 (gdb) break test.c:14 Breakpoint 2 at 0x8048546: file test.c, line 14. (gdb) cont [New process 3475] [Thread debugging using libthread_db enabled] Breakpoint 2, main (argc=1, argv=0xbffff364) at test.c:14 Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.47.el6.i686 (gdb) info inferiors * 1 (gdb) inferior 2
3. 设断点继续调试主进程,主进程产生两个子线程:[Switching to inferior 2 [process 3475] (/home/cnwuwil/labs/c-lab/test)] [Switching to thread 2 (Thread 0xb7fe86c0 (LWP 3475))] #0 (gdb) info inferiors * 2 (gdb) inferior 1 [Switching to inferior 1 [process 3472] (/home/cnwuwil/labs/c-lab/test)] [Switching to thread 1 (Thread 0xb7fe86c0 (LWP 3472))] #0 (gdb) info inferiors * 1 (gdb) break test.c:50
4. 切换到主进程中的子线程,注意:线程2为前面产生的子进程Breakpoint 3 at 0x804867d: file test.c, line 50. (2 locations) (gdb) cont ProcessA: 3472 step1 [New Thread 0xb7fe7b70 (LWP 3562)] ProcessA: 3472 thread 3086911168 step2 Breakpoint 3, processAworker (arg=0x0) at test.c:50 (gdb) info inferiors * 1 (gdb) info threads * 1 Thread 0xb7fe86c0 (LWP 3472) (gdb) thread 3
[Switching to thread 3 (Thread 0xb7fe7b70 (LWP 3562))]#0 (gdb) cont ProcessA: 3472 thread 3086911168 step3 ProcessA: 3472 thread 3086908272 step2 [Switching to Thread 0xb7fe7b70 (LWP 3562)] Breakpoint 3, processAworker (arg=0x0) at test.c:50 (gdb) info threads * 3 Thread 0xb7fe7b70 (LWP 3562) (gdb) thread 1 |
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