Thread counting example with reset
The following example with a reset call illustrates the impact on the group data. The body of the auxiliary thread is the same as before, except for the pm_start_mythread call, which is not necessary in this case.
main()
{
... same initialization as in previous example...
prog.mode.b.count = 1; /* start counting immediately */
pm_set_program_mygroup(&prog);
pthread_create(&threadid, pthread_attr_default, doit, NULL)
... usefull work ....
pm_stop_mythread()
pm_reset_data_mythread()
pthread_join(threadid, &status);
...print auxiliary thread results...
pm_get_data_mygroup(&data)
...print group results...
}In the preceding example, the main thread and the group counting state are both on before the auxiliary thread is created, so the auxiliary thread will inherit that state and start counting immediately.
At the end, data1 is equal to data because the pm_reset_data_mythread automatically subtracted the main thread data from the group data to keep it consistent. In fact, the group data remains equal to the sum of the auxiliary and the main thread data, but in this case, the main thread data is null.