SCHED_SETPARAM(3)          POSIX Programmer's Manual         SCHED_SETPARAM(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
       sched_setparam -- set scheduling parameters (RREEAALLTTIIMMEE)

SSYYNNOOPPSSIISS
       #include <sched.h>

       int sched_setparam(pid_t _p_i_d, const struct sched_param *_p_a_r_a_m);

DDEESSCCRRIIPPTTIIOONN
       The _s_c_h_e_d___s_e_t_p_a_r_a_m() function shall set the scheduling parameters of
       the process specified by _p_i_d to the values specified by the sscchheedd__ppaarraamm
       structure pointed to by _p_a_r_a_m.  The value of the _s_c_h_e_d___p_r_i_o_r_i_t_y member
       in the sscchheedd__ppaarraamm structure shall be any integer within the inclusive
       priority range for the current scheduling policy of the process
       specified by _p_i_d.  Higher numerical values for the priority represent
       higher priorities.  If the value of _p_i_d is negative, the behavior of
       the _s_c_h_e_d___s_e_t_p_a_r_a_m() function is unspecified.

       If a process specified by _p_i_d exists, and if the calling process has
       permission, the scheduling parameters shall be set for the process
       whose process ID is equal to _p_i_d.

       If _p_i_d is zero, the scheduling parameters shall be set for the calling
       process.

       The conditions under which one process has permission to change the
       scheduling parameters of another process are implementation-defined.

       Implementations may require the requesting process to have appropriate
       privileges to set its own scheduling parameters or those of another
       process.

       See _S_c_h_e_d_u_l_i_n_g _P_o_l_i_c_i_e_s for a description on how this function affects
       the scheduling of the threads within the target process.

       If the current scheduling policy for the target process is not
       SCHED_FIFO, SCHED_RR, or SCHED_SPORADIC, the result is implementation-
       defined; this case includes the SCHED_OTHER policy.

       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.

       This function is not atomic with respect to other threads in the
       process. Threads may continue to execute while this function call is in
       the process of changing the scheduling policy for the underlying
       kernel-scheduled entities used by the process contention scope threads.

RREETTUURRNN VVAALLUUEE
       If successful, the _s_c_h_e_d___s_e_t_p_a_r_a_m() function shall return zero.

       If the call to _s_c_h_e_d___s_e_t_p_a_r_a_m() is unsuccessful, the priority shall
       remain unchanged, and the function shall return a value of -1 and set
       _e_r_r_n_o to indicate the error.

EERRRROORRSS
       The _s_c_h_e_d___s_e_t_p_a_r_a_m() function shall fail if:

       EEIINNVVAALL One or more of the requested scheduling parameters is outside
              the range defined for the scheduling policy of the specified
              _p_i_d.

       EEPPEERRMM  The requesting process does not have permission to set the
              scheduling parameters for the specified process, or does not
              have appropriate privileges to invoke _s_c_h_e_d___s_e_t_p_a_r_a_m().

       EESSRRCCHH  No process can be found corresponding to that specified by _p_i_d.

       _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
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _S_c_h_e_d_u_l_i_n_g _P_o_l_i_c_i_e_s, _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(),
       _s_c_h_e_d___s_e_t_s_c_h_e_d_u_l_e_r()

       The Base Definitions volume of POSIX.1-2017, <<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                    SCHED_SETPARAM(3)
