ltt-usertrace/sample-thread-fast.c

   1
   2 #include <pthread.h>
   3 #include <stdio.h>
   4 #include <unistd.h>
   5 #include <stdlib.h>
   6
   7 #define LTT_TRACE
   8 #define LTT_TRACE_FAST
   9 #include <ltt/ltt-facility-user_generic.h>
  10
  11
  12 void *thr1(void *arg)
  13 {
  14         ltt_thread_init();      /* This init is not required : it will be done
  15                                                                                                  automatically anyways at the first tracing call site */
  16         printf("thread 1, thread id : %lu, pid %lu\n", pthread_self(), getpid());
  17
  18         while(1) {
  19                 trace_user_generic_string("Hello world! Have a nice day.");
  20                 sleep(2);
  21         }
  22         pthread_exit((void*)1);
  23 }
  24
  25
  26 /* Example of a _bad_ thread, which still works with the tracing */
  27 void *thr2(void *arg)
  28 {
  29         /* See ? no init */
  30         printf("thread 2, thread id : %lu, pid %lu\n", pthread_self(), getpid());
  31         sleep(1);
  32         while(1) {
  33                 trace_user_generic_string("Hello world! Have a nice day.");
  34                 sleep(2);
  35         }
  36         /* This thread is a bad citizen : returning like this will cause its cancel
  37          * routines not to be executed. This is still detected by the tracer, but only
  38          * when the complete process dies. This is not recommended if you create a
  39          * huge amount of threads */
  40         return ((void*)2);
  41 }
  42
  43
  44 int main()
  45 {
  46         int err;
  47         pthread_t tid1, tid2;
  48         void *tret;
  49
  50         printf("Will trace the following string : Hello world! Have a nice day.\n");
  51         printf("Press CTRL-C to stop.\n");
  52         printf("No file is created with this example : it logs through a kernel\n");
  53         printf("system call. See the LTTng lttctl command to start tracing.\n\n");
  54
  55         printf("thread main, thread id : %lu, pid %lu\n", pthread_self(), getpid());
  56         err = pthread_create(&tid1, NULL, thr1, NULL);
  57         if(err!=0) exit(1);
  58
  59         err = pthread_create(&tid2, NULL, thr2, NULL);
  60         if(err!=0) exit(1);
  61
  62         err = pthread_join(tid1, &tret);
  63         if(err!= 0) exit(1);
  64
  65         err = pthread_join(tid2, &tret);
  66         if(err!= 0) exit(1);
  67
  68         return 0;
  69 }