电商网站做导购,北京网站建设开发,空包网站分站怎么做,社保网站做员工用工备案吗1. 默认设置下#xff0c;在调试多进程程序时GDB只会调试主进程。但是GDB#xff08;V7.0#xff09;支持多进程的
分别以及同时
调试#xff0c;换句话说#xff0c;GDB可以同时调试多个程序。只需要设置follow-fork-mode(默认值#xff1a;parent)和detach-on-fork…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GDBV7.0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。follow-fork-mode detach-on-fork 说明 parent on 只调试主进程GDB默认 child on 只调试子进程 parent off 同时调试两个进程gdb跟主进程子进程block在fork位置 child off 同时调试两个进程gdb跟子进程主进程block在fork位置 设置方法set follow-fork-mode [parent|child] set detach-on-fork [on|off]查询正在调试的进程info inferiors切换调试的进程 inferior infer number添加新的调试进程 add-inferior [-copies n] [-exec executable] ,可以用file executable来分配给inferior可执行文件。其他remove-inferiors infno detach inferior2. GDB默认支持调试多线程跟主线程子线程block在create thread。查询线程info threads切换调试线程thread thread number例程#include stdio.h #include pthread.h void processA(); void processB(); void * processAworker(void *arg); int main(int argc, const char *argv[]) { int pid; pid fork(); if(pid ! 0) processA(); else processB(); return 0; } void processA() { pid_t pid getpid(); char prefix[] ProcessA: ; char tprefix[] thread ; int tstatus; pthread_t pt; printf(%s%lu %s\n, prefix, pid, step1); tstatus pthread_create(pt, NULL, processAworker, NULL); if( tstatus ! 0 ) { printf(ProcessA: Can not create new thread.); } processAworker(NULL); sleep(1); } void * processAworker(void *arg) { pid_t pid getpid(); pthread_t tid pthread_self(); char prefix[] ProcessA: ; char tprefix[] thread ; printf(%s%lu %s%lu %s\n, prefix, pid, tprefix, tid, step2); printf(%s%lu %s%lu %s\n, prefix, pid, tprefix, tid, step3); return NULL; } void processB() { pid_t pid getpid(); char prefix[] ProcessB: ; printf(%s%lu %s\n, prefix, pid, step1); printf(%s%lu %s\n, prefix, pid, step2); printf(%s%lu %s\n, prefix, pid, step3); } 输出[cnwuwilcentos 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 (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 (argc1, argv0xbffff364) at test.c:14 Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.47.el6.i686 (gdb) info inferiors Num Description Executable 2 process 3475 /home/cnwuwil/labs/c-lab/test * 1 process 3472 /home/cnwuwil/labs/c-lab/test 2. 切换到子进程(gdb) inferior 2 [Switching to inferior 2 [process 3475] (/home/cnwuwil/labs/c-lab/test)] [Switching to thread 2 (Thread 0xb7fe86c0 (LWP 3475))] #0 0x00110424 in ?? () (gdb) info inferiors Num Description Executable * 2 process 3475 /home/cnwuwil/labs/c-lab/test 1 process 3472 /home/cnwuwil/labs/c-lab/test (gdb) inferior 1 [Switching to inferior 1 [process 3472] (/home/cnwuwil/labs/c-lab/test)] [Switching to thread 1 (Thread 0xb7fe86c0 (LWP 3472))] #0 main (argc1, argv0xbffff364) at test.c:14 (gdb) info inferiors Num Description Executable 2 process 3475 /home/cnwuwil/labs/c-lab/test * 1 process 3472 /home/cnwuwil/labs/c-lab/test 3. 设断点继续调试主进程主进程产生两个子线程(gdb) break test.c:50 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 (arg0x0) at test.c:50 (gdb) info inferiors Num Description Executable 2 process 3475 /home/cnwuwil/labs/c-lab/test * 1 process 3472 /home/cnwuwil/labs/c-lab/test (gdb) info threads 3 Thread 0xb7fe7b70 (LWP 3562) 0x00110424 in __kernel_vsyscall () 2 Thread 0xb7fe86c0 (LWP 3475) 0x00110424 in ?? () * 1 Thread 0xb7fe86c0 (LWP 3472) processAworker (arg0x0) at 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(gdb) thread 3 [Switching to thread 3 (Thread 0xb7fe7b70 (LWP 3562))]#0 0x00110424 in __kernel_vsyscall () (gdb) cont ProcessA: 3472 thread 3086911168 step3 ProcessA: 3472 thread 3086908272 step2 [Switching to Thread 0xb7fe7b70 (LWP 3562)] Breakpoint 3, processAworker (arg0x0) at test.c:50 (gdb) info threads * 3 Thread 0xb7fe7b70 (LWP 3562) processAworker (arg0x0) at test.c:50 2 Thread 0xb7fe86c0 (LWP 3475) 0x00110424 in ?? () 1 Thread 0xb7fe86c0 (LWP 3472) 0x00110424 in __kernel_vsyscall () (gdb) thread 1
