sched_setscheduler(3c)

1sched_setscheduler(3C)   Standard C Library Functions   sched_setscheduler(3C)
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NAME

6       sched_setscheduler - set scheduling policy and scheduling parameters
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SYNOPSIS

9       #include <sched.h>
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11       int sched_setscheduler(pid_t pid, int policy,
12            const struct sched_param *param);
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DESCRIPTION

16       The sched_setscheduler() function sets the scheduling policy and sched‐
17       uling parameters of the process specified by  pid  to  policy  and  the
18       parameters  specified in the sched_param structure pointed to by param,
19       respectively. The value of the sched_priority member in the sched_param
20       structure  is  any  integer within the inclusive priority range for the
21       scheduling policy specified by policy. The  sched_setscheduler()  func‐
22       tion  ignores  the  other  members of the sched_param structure. If the
23       value of pid is negative,  the  behavior  of  the  sched_setscheduler()
24       function is unspecified.
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27       The  possible values for the policy parameter are defined in the header
28       <sched.h> (see sched.h(3HEAD)):
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31       If a process specified by pid exists and if  the  calling  process  has
32       permission, the scheduling policy and scheduling parameters are set for
33       the process whose process  ID is equal to pid. The  real  or  effective
34       user   ID  of  the  calling  process must match the real or saved (from
35       exec(2)) user  ID of the target process unless the effective  user   ID
36       of the calling process is 0. See Intro(2).
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39       If  pid  is  0, the scheduling policy and scheduling parameters are set
40       for the calling process.
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43       To change the policy of any process to either of the real time policies
44       SCHED_FIFO  or  SCHED_RR,  the  calling  process  must  either have the
45       SCHED_FIFO or SCHED_RR policy or have an effective user ID of 0.
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48       The sched_setscheduler() function is considered successful if  it  suc‐
49       ceeds in setting the scheduling policy and scheduling parameters of the
50       process specified by pid to the values  specified  by  policy  and  the
51       structure pointed to by param, respectively.
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RETURN VALUES

54       Upon  successful completion, the function returns the former scheduling
55       policy of the specified process. If the  sched_setscheduler()  function
56       fails  to  complete successfully, the policy and scheduling paramenters
57       remain unchanged, and the function returns −1 and sets errno  to  indi‐
58       cate the error.
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ERRORS

61       The sched_setscheduler() function will fail if:
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63       EINVAL    The value of policy is invalid, or one or more of the parame‐
64                 ters contained in param is outside the valid  range  for  the
65                 specified scheduling policy.
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68       EPERM     The requesting process does not have permission to set either
69                 or both of the scheduling parameters or the scheduling policy
70                 of the specified process.
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73       ESRCH     No  process  can  be found corresponding to that specified by
74                 pid.
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ATTRIBUTES

78       See attributes(5) for descriptions of the following attributes:
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83       ┌─────────────────────────────┬─────────────────────────────┐
84       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
85       ├─────────────────────────────┼─────────────────────────────┤
86       │Interface Stability          │Committed                    │
87       ├─────────────────────────────┼─────────────────────────────┤
88       │MT-Level                     │MT-Safe                      │
89       ├─────────────────────────────┼─────────────────────────────┤
90       │Standard                     │See standards(5).            │
91       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

RETURN VALUES

ERRORS

ATTRIBUTES

SEE ALSO