Creating a Thread With a Specified Priority

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, xxx the thread, and then reset the priority.

Example 3-2 shows an example of this.

Example 3-2 Creating a Prioritized Thread

#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, &param);

/* set the priority; others are unchanged */
param.sched_priority = newprio;

/* setting the new scheduling param */
ret = pthread_attr_setschedparam (&tattr, &param);

/* with new priority specified */
ret = pthread_create (&tid, &tattr, func, arg);