PTHREAD_GETSCHEDPARAM(3)   POSIX Programmer's Manual  PTHREAD_GETSCHEDPARAM(3)



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NNAAMMEE
       pthread_getschedparam, pthread_setschedparam -- dynamic thread
       scheduling parameters access (RREEAALLTTIIMMEE TTHHRREEAADDSS)

SSYYNNOOPPSSIISS
       #include <pthread.h>

       int pthread_getschedparam(pthread_t _t_h_r_e_a_d, int *restrict _p_o_l_i_c_y,
           struct sched_param *restrict _p_a_r_a_m);
       int pthread_setschedparam(pthread_t _t_h_r_e_a_d, int _p_o_l_i_c_y,
           const struct sched_param *_p_a_r_a_m);

DDEESSCCRRIIPPTTIIOONN
       The _p_t_h_r_e_a_d___g_e_t_s_c_h_e_d_p_a_r_a_m() and _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m() 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 the
       sscchheedd__ppaarraamm structure is the priority _s_c_h_e_d___p_r_i_o_r_i_t_y.  For SCHED_OTHER,
       the affected scheduling parameters are implementation-defined.

       The _p_t_h_r_e_a_d___g_e_t_s_c_h_e_d_p_a_r_a_m() function shall retrieve the scheduling
       policy and scheduling parameters for the thread whose thread ID is
       given by _t_h_r_e_a_d and shall store those values in _p_o_l_i_c_y and _p_a_r_a_m,
       respectively. The priority value returned from _p_t_h_r_e_a_d___g_e_t_s_c_h_e_d_p_a_r_a_m()
       shall be the value specified by the most recent
       _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m(), _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_r_i_o(), or _p_t_h_r_e_a_d___c_r_e_a_t_e()
       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. The _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m() function shall set the
       scheduling policy and associated scheduling parameters for the thread
       whose thread ID is given by _t_h_r_e_a_d to the policy and associated
       parameters provided in _p_o_l_i_c_y and _p_a_r_a_m, respectively.

       The _p_o_l_i_c_y 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, _p_r_i_o_r_i_t_y.

       If _POSIX_THREAD_SPORADIC_SERVER is defined, then the _p_o_l_i_c_y argument
       may have the value SCHED_SPORADIC, with the exception for the
       _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m() 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 parameters _s_c_h_e_d___s_s___l_o_w___p_r_i_o_r_i_t_y, _s_c_h_e_d___s_s___r_e_p_l___p_e_r_i_o_d,
       _s_c_h_e_d___s_s___i_n_i_t___b_u_d_g_e_t, _s_c_h_e_d___p_r_i_o_r_i_t_y, and _s_c_h_e_d___s_s___m_a_x___r_e_p_l.  The
       specified _s_c_h_e_d___s_s___r_e_p_l___p_e_r_i_o_d shall be greater than or equal to the
       specified _s_c_h_e_d___s_s___i_n_i_t___b_u_d_g_e_t for the function to succeed; if it is
       not, then the function shall fail. The value of _s_c_h_e_d___s_s___m_a_x___r_e_p_l 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
       the _s_c_h_e_d___s_s___r_e_p_l___p_e_r_i_o_d and _s_c_h_e_d___s_s___i_n_i_t___b_u_d_g_e_t values are stored as
       provided by this function or are rounded to align with the resolution
       of the clock being used.

       If the _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m() function fails, the scheduling
       parameters shall not be changed for the target thread.

RREETTUURRNN VVAALLUUEE
       If successful, the _p_t_h_r_e_a_d___g_e_t_s_c_h_e_d_p_a_r_a_m() and _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m()
       functions shall return zero; otherwise, an error number shall be
       returned to indicate the error.

EERRRROORRSS
       The _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m() function shall fail if:

       EENNOOTTSSUUPP
              An attempt was made to set the policy or scheduling parameters
              to an unsupported value.

       EENNOOTTSSUUPP
              An attempt was made to dynamically change the scheduling policy
              to SCHED_SPORADIC, and the implementation does not support this
              change.

       The _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_a_r_a_m() function may fail if:

       EEIINNVVAALL The value specified by _p_o_l_i_c_y or one of the scheduling
              parameters associated with the scheduling policy _p_o_l_i_c_y is
              invalid.

       EEPPEERRMM  The caller does not have appropriate privileges to set either
              the scheduling parameters or the scheduling policy of the
              specified thread.

       EEPPEERRMM  The 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 [[EEIINNTTRR]].

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       None.

RRAATTIIOONNAALLEE
       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
       [[EESSRRCCHH]] error.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _p_t_h_r_e_a_d___s_e_t_s_c_h_e_d_p_r_i_o(), _s_c_h_e_d___g_e_t_p_a_r_a_m(), _s_c_h_e_d___g_e_t_s_c_h_e_d_u_l_e_r()

       The Base Definitions volume of POSIX.1-2017, <<pptthhrreeaadd..hh>>, <<sscchheedd..hh>>

CCOOPPYYRRIIGGHHTT
       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 at http://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, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017             PTHREAD_GETSCHEDPARAM(3)
