NAME

pthread_attr_getschedparam pthread_attr_setschedparam — get and set the schedparam attribute

SYNOPSIS

[THR]
#include <pthread.h>

int pthread_attr_getschedparam(const pthread_attr_t *restrict attr,
       struct sched_param *restrict param);
int pthread_attr_setschedparam(pthread_attr_t *restrict attr,
       const struct sched_param *restrict param);

DESCRIPTION

The pthread_attr_getschedparam (), and pthread_attr_setschedparam () functions, respectively, shall get and set the scheduling parameter attributes in the attr argument. The contents of the param structure are defined in the <sched.h> header. For the SCHED_FIFO and SCHED_RR policies, the only required member of param is sched_priority.

[TSP] For the SCHED_SPORADIC policy, the required members of the param structure are sched_priority, sched_ss_low_priority, sched_ss_repl_period, sched_ss_init_budget, and sched_ss_max_repl. The specified sched_ss_repl_period must be greater than or equal to the specified sched_ss_init_budget for the function to succeed; if it is not, then the function shall fail. The value of sched_ss_max_repl shall be within the inclusive range [1, {SS_REPL_MAX}] for the function to succeed; if not, the function shall fail.

RETURN VALUE

If successful, the pthread_attr_getschedparam () and pthread_attr_setschedparam () functions shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

The pthread_attr_setschedparam () function may fail if:

[EINVAL]

The value of param is not valid.

[ENOTSUP]

An attempt was made to set the attribute to an unsupported value.

These functions shall not return an error code of [EINTR].

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

After these attributes have been set, a thread can be created with the specified attributes using pthread_create(3). Using these routines does not affect the current running thread.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_attr_destroy(3) , pthread_attr_getscope(3) , pthread_attr_getinheritsched(3) , pthread_attr_getschedpolicy(3) , pthread_create(3) , the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <pthread.h>, <sched.h>

CHANGE HISTORY

First released in Issue 5. Included for alignment with the POSIX Threads Extension.

Issue 6

The pthread_attr_getschedparam () and pthread_attr_setschedparam () functions are marked as part of the Threads option.

The SCHED_SPORADIC scheduling policy is added for alignment with IEEE Std 1003.1d-1999.

The restrict keyword is added to the pthread_attr_getschedparam () and pthread_attr_setschedparam () prototypes for alignment with the ISO/IEC 9899:1999 (“ISO C99”) standard.

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