- execution scheduling
The <sched.h> header defines the sched_param structure, which contains the scheduling parameters required for implementation of each supported scheduling policy. This structure contains the following member:
int sched_priority process execution scheduling priority
Each process is controlled by an associated scheduling policy and priority. Associated with each policy is a priority range. Each policy definition specifies the minimum priority range for that policy. The priority ranges for each policy may overlap the priority ranges of other policies.
The scheduling policies are indicated by the values of the following symbolic constants:
Processes are scheduled according to the First-In-First-Out (FIFO) policy. Processes scheduled to this policy, if not pre-empted by a higher priority or interrupted by a signal, will proceed until completion.
Processes are scheduled according to the Round-Robin (RR) policy. Processes scheduled to this policy, if not pre-empted by a higher priority or interrupted by a signal, will execute for a time period, returned by sched_rr_get_interval(3RT) or by the system.
Processes are scheduled according to the Inter-Active Class (IA) policy as described in priocntl(2).
Processes are scheduled according to another policy not described above.
The values of these constants are distinct.
Inclusion of the <sched.h> header will make visible symbols defined in the header <time.h>.