You can set the priority attribute before creating the thread. The child thread is created with the new priority that is specified in the sched_param structure (this structure also contains other scheduling information).
It is always a good idea to get the existing parameters, change the priority, create the thread, and then reset the priority.
Example 3–2 shows an example of this.
#include <pthread.h> #include <sched.h> pthread_attr_t tattr; pthread_t tid; int ret; int newprio = 20; sched_param param; /* initialized with default attributes */ ret = pthread_attr_init (&tattr); /* safe to get existing scheduling param */ ret = pthread_attr_getschedparam (&tattr, ¶m); /* set the priority; others are unchanged */ param.sched_priority = newprio; /* setting the new scheduling param */ ret = pthread_attr_setschedparam (&tattr, ¶m); /* with new priority specified */ ret = pthread_create (&tid, &tattr, func, arg);