sched_setparam(3c) [opensolaris man page]

sched_setparam(3C)					   Standard C Library Functions 					sched_setparam(3C)

NAME

       sched_setparam - set scheduling parameters

SYNOPSIS

       #include <sched.h>

       int sched_setparam(pid_t pid, const struct sched_param *param);

DESCRIPTION

       The  sched_setparam()  function	sets  the scheduling parameters of the process specified by pid to the values specified by the sched_param
       structure pointed to by param. The value of the sched_priority member in the sched_param structure is any integer within the inclusive pri-
       ority  range  for  the current scheduling policy of the process specified by pid. Higher numerical values for the priority represent higher
       priorities. If the value of pid is negative, the behavior of the sched_setparam() function is unspecified.

       If a process specified by pid exists and if the calling process has permission, the scheduling parameters will be set for the process whose
       process	ID  is	equal to pid. The real or effective user ID of the calling process must match the  real or saved (from exec(2)) user ID of
       the target process unless the effective user ID of the calling process is 0. See Intro(2).

       If pid is zero, the scheduling parameters will be set for the calling process.

       The target process, whether it is running or not running, resumes execution after all other runnable processes of equal or greater priority
       have been scheduled to run.

       If  the	priority  of  the  process specified by the pid argument is set higher than that of the lowest priority running process and if the
       specified process is ready to run, the process specified by the pid argument preempts a lowest priority running process. Similarly, if  the
       process	calling sched_setparam() sets its own priority lower than that of one or more other non-empty process lists, then the process that
       is the head of the highest priority list also preempts the calling process. Thus, in either case, the originating process might not receive
       notification of the completion of the requested priority change until the higher priority process has executed.

RETURN VALUES

       If successful, the sched_setparam() function returns 0.

       If the call to sched_setparam() is unsuccessful, the priority remains unchanged, and the function returns -1 and sets errno to indicate the
       error.

ERRORS

       The sched_setparam() function will fail if:

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

       EPERM	 The requesting process does not have permission to set the scheduling parameters for the specified process, or does not have  the
		 appropriate privilege to invoke sched_setparam().

       ESRCH	 No process can be found corresponding to that specified by pid.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |ATTRIBUTE TYPE		     |ATTRIBUTE VALUE		   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       Intro(2),  exec(2),  librt(3LIB),  sched.h(3HEAD), sched_getparam(3C), sched_getscheduler(3C), sched_setscheduler(3C), attributes(5), stan-
       dards(5)

SunOS 5.11							    1 Apr 2008							sched_setparam(3C)

sched_setparam(3)					     Library Functions Manual						 sched_setparam(3)

NAME

       sched_setparam - Sets the scheduling parameters of the specified process (P1003.1b)

LIBRARY

       Realtime Library (librt.so, librt.a)

SYNOPSIS

       #include <sched.h>

       int sched_setparam (
       pid_t pid,
       const struct sched_param *param);

PARAMETERS

       pid     Specifies  the  ID  of  the  process  whose scheduling parameters are set. If pid is zero, the scheduling parameters of the calling
	       process are set.

       *param  Specifies a pointer to a sched_param structure, which contains the scheduling parameters of the specified process.  Currently,  the
	       sched_param structure contains only a priority field.  The value of the priority value is any integer within the priority range for
	       the current scheduling policy of the process specified by pid.

DESCRIPTION

       The sched_setparam function changes the scheduling parameters of a process. Setting priorities such that the most critical process has  the
       highest priority allows applications to determine more effectively when a process will run.

       At  run	time,  a process starts out with an initial priority of SCHED_PRIO_USER_MAX. A call to the sched_setparam function that raises the
       priority of a process also raises the maximum priority for the process. This higher maximum priority exists for the life of the process	or
       until  the  priority  is  set to a new, higher priority through another call to the sched_setparam function. The maximum priority cannot be
       adjusted downward, but subsequent calls to the sched_setparam or sched_setscheduler functions can specify that a process  run  at  a  lower
       priority.

       You  must have superuser privileges to set the priority above the user maximum, SCHED_PRIO_USER_MAX.  A superuser can set the priority out-
       side the range of the specified pid's scheduling policy.

       When the function completes, the target process resumes execution after all other runnable processes  of  equal	or  greater  priority  are
       scheduled to run.  If the priority of the target process is set higher than that of the calling process, and if the target process is ready
       to run, then the target process will preempt the calling process. If the calling process  set  its  own	priority  lower  than  some  other
       process,  then  the other process will preempt the calling process. In either situation, the calling process might not receive notification
       of the completion of the requested priority change until the target process has executed.

       The scheduling parameters of the process as indicated by pid are obtained with a call to the sched_getparam function.

       The priority of a process is inherited across fork and exec calls.

RETURN VALUES

       On a successful call to the sched_setparam function, the scheduling parameters are set and a value of 0 (zero) is returned.  On	an  unsuc-
       cessful call, a value of -1 is returned and errno is set to indicate that an error occurred and the priority is unchanged.

ERRORS

       The sched_setparam function fails under the following conditions:

       [EINVAL]       One  or  more of the requested scheduling parameters is outside the range defined for the specified pid's scheduling policy.
		      This error does not apply for superusers.

       [EPERM]	      The requesting process does not have permission to set the scheduling parameters for the specified process, nor does it have
		      appropriate privilege to invoke the sched_setparam function.

       [ESRCH]	      No process can be found corresponding to that specified by pid.

RELATED INFORMATION

       Functions: getpid(2), sched_getparam(3), sched_getscheduler(3), sched_setscheduler(3)

       Guide to Realtime Programming delim off

																 sched_setparam(3)