man3/pthread_attr_setschedparam.3

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  26 .TH PTHREAD_ATTR_SETSCHEDPARAM 3 2017-09-15 "Linux" "Linux Programmer's Manual"
  27 .SH NAME
  28 pthread_attr_setschedparam, pthread_attr_getschedparam \- set/get
  29 scheduling parameter attributes in thread attributes object
  30 .SH SYNOPSIS
  31 .nf
  32 .B #include <pthread.h>
  33 .PP
  34 .BI "int pthread_attr_setschedparam(pthread_attr_t *" attr ,
  35 .BI "                               const struct sched_param *" param );
  36 .BI "int pthread_attr_getschedparam(const pthread_attr_t *" attr ,
  37 .BI "                               struct sched_param *" param );
  38 .PP
  39 Compile and link with \fI\-pthread\fP.
  40 .fi
  41 .SH DESCRIPTION
  42 The
  43 .BR pthread_attr_setschedparam ()
  44 function sets the scheduling parameter attributes of the
  45 thread attributes object referred to by
  46 .IR attr
  47 to the values specified in the buffer pointed to by
  48 .IR param .
  49 These attributes determine the scheduling parameters of
  50 a thread created using the thread attributes object
  51 .IR attr .
  52 .PP
  53 The
  54 .BR pthread_attr_getschedparam ()
  55 returns the scheduling parameter attributes of the thread attributes object
  56 .IR attr
  57 in the buffer pointed to by
  58 .IR param .
  59 .PP
  60 Scheduling parameters are maintained in the following structure:
  61 .PP
  62 .in +4n
  63 .EX
  64 struct sched_param {
  65     int sched_priority;     /* Scheduling priority */
  66 };
  67 .EE
  68 .in
  69 .PP
  70 As can be seen, only one scheduling parameter is supported.
  71 For details of the permitted ranges for scheduling priorities
  72 in each scheduling policy, see
  73 .BR sched (7).
  74 .PP
  75 In order for the parameter setting made by
  76 .BR pthread_attr_setschedparam ()
  77 to have effect when calling
  78 .BR pthread_create (3),
  79 the caller must use
  80 .BR pthread_attr_setinheritsched (3)
  81 to set the inherit-scheduler attribute of the attributes object
  82 .I attr
  83 to
  84 .BR PTHREAD_EXPLICIT_SCHED .
  85 .SH RETURN VALUE
  86 On success, these functions return 0;
  87 on error, they return a nonzero error number.
  88 .SH ERRORS
  89 .BR pthread_attr_setschedparam ()
  90 can fail with the following error:
  91 .TP
  92 .B EINVAL
  93 The priority specified in
  94 .I param
  95 does not make sense for the current scheduling policy of
  96 .IR attr .
  97 .PP
  98 POSIX.1 also documents an
  99 .B ENOTSUP
 100 error for
 101 .BR pthread_attr_setschedparam ().
 102 This value is never returned on Linux
 103 (but portable and future-proof applications should nevertheless
 104 handle this error return value).
 105 .\" .SH VERSIONS
 106 .\" Available since glibc 2.0.
 107 .SH ATTRIBUTES
 108 For an explanation of the terms used in this section, see
 109 .BR attributes (7).
 110 .TS
 111 allbox;
 112 lbw29 lb lb
 113 l l l.
 114 Interface       Attribute       Value
 115 T{
 116 .BR pthread_attr_setschedparam (),
 117 .BR pthread_attr_getschedparam ()
 118 T}      Thread safety   MT-Safe
 119 .TE
 120 .SH CONFORMING TO
 121 POSIX.1-2001, POSIX.1-2008.
 122 .SH NOTES
 123 See
 124 .BR pthread_attr_setschedpolicy (3)
 125 for a list of the thread scheduling policies supported on Linux.
 126 .SH EXAMPLE
 127 See
 128 .BR pthread_setschedparam (3).
 129 .SH SEE ALSO
 130 .ad l
 131 .nh
 132 .BR sched_get_priority_min (2),
 133 .BR pthread_attr_init (3),
 134 .BR pthread_attr_setinheritsched (3),
 135 .BR pthread_attr_setschedpolicy (3),
 136 .BR pthread_create (3),
 137 .BR pthread_setschedparam (3),
 138 .BR pthread_setschedprio (3),
 139 .BR pthreads (7),
 140 .BR sched (7)