多线程写日志时，输出的线程id不是子线程的id

[ahchengrui]

修改linux demo为多线程模式，verbose里面的tid不是子线程本身的id？ I/elog [12-25 18:28:36] EasyLogger V2.0.3 is initialize success. do multithread test... start create thread........ start create thread........ id=0 tid =3152430848 id=1 tid =3144038144 elog_output----tid:13995 A/main [12-25 18:28:36 pid:31856 tid:13995] (main.c test_elog:86)Hello EasyLogger! 0 E/main [12-25 18:28:36] Hello EasyLogger! 0 W/main [12-25 18:28:36] Hello EasyLogger! 0 I/main [12-25 18:28:36] Hello EasyLogger! 0 elog_output----tid:13995 elog_output----tid:13995 elog_output----tid:13995 A/main [12-25 18:28:36 pid:31856 tid:13995] (main.c test_elog:86)Hello EasyLogger! 1 E/main [12-25 18:28:36] Hello EasyLogger! 1 W/main [12-25 18:28:36] Hello EasyLogger! 1 I/main [12-25 18:28:36] Hello EasyLogger! 1 elog_output----tid:13995 elog_output----tid:13995 D/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:90)Hello EasyLogger! 0 V/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:91)Hello EasyLogger! 0 D/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:90)Hello EasyLogger! 1 V/main [12-25 18:28:36 pid:31856 tid:13995] (main.c:91)Hello EasyLogger! 1

[armink]

咦~~你看下你的 tid 跟自带 demo 获取 tid 的方式一样吗？

https://github.com/armink/EasyLogger/blob/f4af95b656424f74f6ae8a505fd048291ab32056/demo/os/linux/easylogger/port/elog_port.c#L110-L121

[ahchengrui]

demo/os/linux/main.c 代码修改如下 ` /* start EasyLogger */ elog_start();

/* test logger output */
_test_multithread();

return EXIT_SUCCESS;

} static void _test_multithread() { pthread_t ptt[2]; int i; for (i = 0; i < 2; ++i) { printf("start create thread........\n"); pthread_create(&ptt[i], NULL, test_elog, i); }
for (i = 0; i < 2; ++i) { pthread_join(ptt[i], NULL); }
} void test_elog(void *arg) { int id = (int )arg; static char cur_thread_info[10] = { 0 };
snprintf(cur_thread_info, 10, "tid:%04ld", pthread_self()); printf("pthread id is %s\n",cur_thread_info); while(true) { / test log output for all level */ log_a("Hello EasyLogger! %d", id); log_e("Hello EasyLogger! %d", id); log_w("Hello EasyLogger! %d", id); log_i("Hello EasyLogger! %d", id); log_d("Hello EasyLogger! %d", id); log_v("Hello EasyLogger! %d", id); // elog_raw("Hello EasyLogger!"); sleep(5); } } ` 运行结果如下： I/elog [12-25 21:44:15] EasyLogger V2.0.3 is initialize success. start create thread........ start create thread........ pthread id is tid:20511 pthread id is tid:20427 elog_output----tid:14062 A/main [12-25 21:44:15 pid:23758 tid:14062] (main.c test_elog:81)Hello EasyLogger! 0 E/main [12-25 21:44:15] Hello EasyLogger! 0 W/main [12-25 21:44:15] Hello EasyLogger! 0 I/main [12-25 21:44:15] Hello EasyLogger! 0 elog_output----tid:14062 elog_output----tid:14062 D/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:85)Hello EasyLogger! 0 V/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:86)Hello EasyLogger! 0 elog_output----tid:14062 A/main [12-25 21:44:15 pid:23758 tid:14062] (main.c test_elog:81)Hello EasyLogger! 1 E/main [12-25 21:44:15] Hello EasyLogger! 1 W/main [12-25 21:44:15] Hello EasyLogger! 1 I/main [12-25 21:44:15] Hello EasyLogger! 1 elog_output----tid:14062 elog_output----tid:14062 D/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:85)Hello EasyLogger! 1 V/main [12-25 21:44:15 pid:23758 tid:14062] (main.c:86)Hello EasyLogger! 1

获取到的线程id与V/main里面打印的线程id不一致

[armink]

pthread 我现在用的不多，能深入查下原因吗？

[tianlongqin]

线程号不一致的问题，估计是默认使用的异步输出，所以打印的线程号是异步线程的id。

[armink]

应该不是，日志帧内容在转到异步输出前，就已经定好了

[tianlongqin]

我才看了下代码，发现了问题，是因为snprintf(cur_thread_info, 10, "tid:%ld", pthread_self());这行代码导致的。 1、组包用的是%ld，和%d的输出不一样。 2、id长度很大，组包的时候有截断，无法输出全部id号。

[armink]

@tianlongqin 分析的有道理 👍

[ice2767]

• snprintf(cur_thread_info, 10, "tid:%04ld", pthread_self()); ld要修改成lu才能正常打印出pthread_self()的返回值
• pthread_self()的返回线程ID非top -H显示的线程ID,建议将pthread_self()更换成syscall的方式