_lwp_setscheduler(2)_lwp_setscheduler(2)NAME_lwp_setscheduler() - set LWP(Lightweight Process) scheduling policy
and parameters
SYNOPSISDESCRIPTION
The function allows the scheduling policy and parameters of an individ‐
ual LWP in any process to be set. For and the only required member of
the sched_param structure is the priority sched_priority.
The cmd argument determines the action to be performed by the system
call and supports one of the following values. Other values of cmd are
reserved for use by HP and may change without notice. The behavior of
_lwp_setscheduler is undefined if any other value is passed to the cmd
argument and it may change without notice.
This request sets the scheduling policy and associated schedul‐
ing parameters
for the LWP whose LWP ID is specified by target_lwp to
the policy and associated parameters provided in policy
and param respectively. The LWPID specified by tar‐
get_lwp can be in any process. If the value of tar‐
get_lwp is zero (0), the target LWP will be the calling
LWP.
This request sets the scheduling policy and associated schedul‐
ing parameters
for all LWPs in the target process specified by tar‐
get_lwp to the policy and associated parameters provided
in policy and param, respectively. For this request, the
PID value should be passed in the target_lwp parameter.
The policy and param arguments are stored in the process
so they may be assigned to the child process during a
fork operation.
If the function fails, no scheduling parameters or policies shall be
changed for the specified LWP(s).
Appropriate privileges are required to change the scheduling parameters
of another LWP. The calling LWP must have appropriate privileges or be
a member of a group having access to successfully call
Refer to the rtsched(2) manpage for a complete description of schedul‐
ing policies and priorities available. is similar to the function
except that it operates on lightweight processes instead of processes.
RETURN VALUE
Upon successful completion, returns with a value of 0; otherwise, it
returns an error number to indicate the error. The variable is NOT set
if an error occurs.
ERRORS
For each of the following conditions, if the condition is detected, the
function fails and returns the corresponding error number:
The target process could not be accessed due to compartmental
restrictions.
The param parameter points to an illegal address.
The cmd parameter is invalid.
The value of the
policy parameter is invalid, or the param parame‐
ter is NULL, or one or more parameters contained
in param is outside the valid range for the spec‐
ified scheduling policy.
The requesting LWP does not have permission to set the schedul‐
ing policy
and parameter for the specified LWP(s).
No LWP can be found corresponding to that specified by
target_lwp.
No process can be found corresponding to that specified by
target_lwp for the request.
WARNINGS
In general, the POSIX pthread interfaces should be used by multi-
threaded applications. This system call may be used directly only when
the application has a need to operate on LWPs in another process. This
system call may result in undefined behavior if the usage is mixed with
POSIX pthread APIs.
SEE ALSO_lwp_getscheduler(2), sched_setscheduler(2), pthread_setschedparam(3t).
_lwp_setscheduler(2)
