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PROLOG |NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |ERRORS |EXAMPLES |APPLICATION USAGE |RATIONALE |FUTURE DIRECTIONS |SEE ALSO |COPYRIGHT | |
PTHREAD...HEDPARAM(3P) POSIX Programmer's ManualPTHREAD...HEDPARAM(3P)This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
pthread_getschedparam, pthread_setschedparam — dynamic thread scheduling parameters access (REALTIME THREADS)
#include <pthread.h> int pthread_getschedparam(pthread_tthread, int *restrictpolicy, struct sched_param *restrictparam); int pthread_setschedparam(pthread_tthread, intpolicy, const struct sched_param *param);
Thepthread_getschedparam() andpthread_setschedparam() functions shall, respectively, get and set the scheduling policy and parameters of individual threads within a multi-threaded process to be retrieved and set. For SCHED_FIFO and SCHED_RR, the only required member of thesched_paramstructure is the prioritysched_priority. For SCHED_OTHER, the affected scheduling parameters are implementation-defined. Thepthread_getschedparam() function shall retrieve the scheduling policy and scheduling parameters for the thread whose thread ID is given bythread and shall store those values inpolicy andparam, respectively. The priority value returned frompthread_getschedparam() shall be the value specified by the most recentpthread_setschedparam(),pthread_setschedprio(), orpthread_create() call affecting the target thread. It shall not reflect any temporary adjustments to its priority as a result of any priority inheritance or ceiling functions. Thepthread_setschedparam() function shall set the scheduling policy and associated scheduling parameters for the thread whose thread ID is given bythread to the policy and associated parameters provided inpolicy andparam, respectively. Thepolicy parameter may have the value SCHED_OTHER, SCHED_FIFO, or SCHED_RR. The scheduling parameters for the SCHED_OTHER policy are implementation-defined. The SCHED_FIFO and SCHED_RR policies shall have a single scheduling parameter,priority. If _POSIX_THREAD_SPORADIC_SERVER is defined, then thepolicy argument may have the value SCHED_SPORADIC, with the exception for thepthread_setschedparam() function that if the scheduling policy was not SCHED_SPORADIC at the time of the call, it is implementation-defined whether the function is supported; in other words, the implementation need not allow the application to dynamically change the scheduling policy to SCHED_SPORADIC. The sporadic server scheduling policy has the associated parameterssched_ss_low_priority,sched_ss_repl_period,sched_ss_init_budget,sched_priority, andsched_ss_max_repl. The specifiedsched_ss_repl_period shall be greater than or equal to the specifiedsched_ss_init_budget for the function to succeed; if it is not, then the function shall fail. The value ofsched_ss_max_repl shall be within the inclusive range [1,{SS_REPL_MAX}] for the function to succeed; if not, the function shall fail. It is unspecified whether thesched_ss_repl_period andsched_ss_init_budget values are stored as provided by this function or are rounded to align with the resolution of the clock being used. If thepthread_setschedparam() function fails, the scheduling parameters shall not be changed for the target thread.If successful, thepthread_getschedparam() andpthread_setschedparam() functions shall return zero; otherwise, an error number shall be returned to indicate the error.
Thepthread_setschedparam() function shall fail if:ENOTSUP An attempt was made to set the policy or scheduling parameters to an unsupported value.ENOTSUP An attempt was made to dynamically change the scheduling policy to SCHED_SPORADIC, and the implementation does not support this change. Thepthread_setschedparam() function may fail if:EINVALThe value specified bypolicy or one of the scheduling parameters associated with the scheduling policypolicy is invalid.EPERMThe caller does not have appropriate privileges to set either the scheduling parameters or the scheduling policy of the specified thread.EPERMThe implementation does not allow the application to modify one of the parameters to the value specified. These functions shall not return an error code of[EINTR].The following sections are informative.
None.
None.
If an implementation detects use of a thread ID after the end of its lifetime, it is recommended that the function should fail and report an[ESRCH]error.
None.
pthread_setschedprio(3p),sched_getparam(3p),sched_getscheduler(3p) The Base Definitions volume of POSIX.1‐2017,pthread.h(0p),sched.h(0p)
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online athttp://www.opengroup.org/unix/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, seehttps://www.kernel.org/doc/man-pages/reporting_bugs.html .IEEE/The Open Group 2017PTHREAD...HEDPARAM(3P)Pages that refer to this page:pthread.h(0p), pthread_setschedparam(3p), pthread_setschedprio(3p)
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