man3/pthread_attr_setinheritsched.3

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  26 .TH PTHREAD_ATTR_SETINHERITSCHED 3 2015-08-08 "Linux" "Linux Programmer's Manual"
  27 .SH NAME
  28 pthread_attr_setinheritsched, pthread_attr_getinheritsched \- set/get
  29 inherit-scheduler attribute in thread attributes object
  30 .SH SYNOPSIS
  31 .nf
  32 .B #include <pthread.h>
  33
  34 .BI "int pthread_attr_setinheritsched(pthread_attr_t *" attr ,
  35 .BI "                                 int " inheritsched );
  36 .BI "int pthread_attr_getinheritsched(const pthread_attr_t *" attr ,
  37 .BI "                                 int *" inheritsched );
  38 .sp
  39 Compile and link with \fI\-pthread\fP.
  40 .fi
  41 .SH DESCRIPTION
  42 The
  43 .BR pthread_attr_setinheritsched ()
  44 function sets the inherit-scheduler attribute of the
  45 thread attributes object referred to by
  46 .IR attr
  47 to the value specified in
  48 .IR inheritsched .
  49 The inherit-scheduler attribute determines whether a thread created using
  50 the thread attributes object
  51 .I attr
  52 will inherit its scheduling attributes from the calling thread
  53 or whether it will take them from
  54 .IR attr .
  55
  56 The following scheduling attributes are affected by the
  57 inherit-scheduler attribute:
  58 scheduling policy
  59 .RB ( pthread_attr_setschedpolicy (3)),
  60 scheduling priority
  61 .RB ( pthread_attr_setschedparam (3)),
  62 and contention scope
  63 .RB ( pthread_attr_setscope (3)).
  64
  65 The following values may be specified in
  66 .IR inheritsched :
  67 .TP
  68 .B PTHREAD_INHERIT_SCHED
  69 Threads that are created using
  70 .I attr
  71 inherit scheduling attributes from the creating thread;
  72 the scheduling attributes in
  73 .I attr
  74 are ignored.
  75 .TP
  76 .B PTHREAD_EXPLICIT_SCHED
  77 Threads that are created using
  78 .I attr
  79 take their scheduling attributes from the values specified
  80 by the attributes object.
  81 .\" FIXME Document the defaults for scheduler settings
  82 .PP
  83 The default setting of the inherit-scheduler attribute in
  84 a newly initialized thread attributes object is
  85 .BR PTHREAD_INHERIT_SCHED .
  86
  87 The
  88 .BR pthread_attr_getinheritsched ()
  89 returns the inherit-scheduler attribute of the thread attributes object
  90 .IR attr
  91 in the buffer pointed to by
  92 .IR inheritsched .
  93 .SH RETURN VALUE
  94 On success, these functions return 0;
  95 on error, they return a nonzero error number.
  96 .SH ERRORS
  97 .BR pthread_attr_setinheritsched ()
  98 can fail with the following error:
  99 .TP
 100 .B EINVAL
 101 Invalid value in
 102 .IR inheritsched .
 103 .PP
 104 POSIX.1 also documents an optional
 105 .B ENOTSUP
 106 error ("attempt was made to set the attribute to an unsupported value") for
 107 .BR pthread_attr_setinheritsched ().
 108 .\" .SH VERSIONS
 109 .\" Available since glibc 2.0.
 110 .SH ATTRIBUTES
 111 For an explanation of the terms used in this section, see
 112 .BR attributes (7).
 113 .TS
 114 allbox;
 115 lbw31 lb lb
 116 l l l.
 117 Interface       Attribute       Value
 118 T{
 119 .BR pthread_attr_setinheritsched (),
 120 .BR pthread_attr_getinheritsched ()
 121 T}      Thread safety   MT-Safe
 122 .TE
 123 .SH CONFORMING TO
 124 POSIX.1-2001, POSIX.1-2008.
 125 .SH BUGS
 126 As at glibc 2.8, if a thread attributes object is initialized using
 127 .BR pthread_attr_init (3),
 128 then the scheduling policy of the attributes object is set to
 129 .BR SCHED_OTHER
 130 and the scheduling priority is set to 0.
 131 However, if the inherit-scheduler attribute is then set to
 132 .BR PTHREAD_EXPLICIT_SCHED ,
 133 then a thread created using the attribute object
 134 wrongly inherits its scheduling attributes from the creating thread.
 135 This bug does not occur if either the scheduling policy or
 136 scheduling priority attribute is explicitly set
 137 in the thread attributes object before calling
 138 .BR pthread_create (3).
 139 .\" FIXME . Track status of the following bug:
 140 .\" http://sourceware.org/bugzilla/show_bug.cgi?id=7007
 141 .SH EXAMPLE
 142 See
 143 .BR pthread_setschedparam (3).
 144 .SH SEE ALSO
 145 .ad l
 146 .nh
 147 .BR pthread_attr_init (3),
 148 .BR pthread_attr_setschedparam (3),
 149 .BR pthread_attr_setschedpolicy (3),
 150 .BR pthread_attr_setscope (3),
 151 .BR pthread_create (3),
 152 .BR pthread_setschedparam (3),
 153 .BR pthread_setschedprio (3),
 154 .BR pthreads (7),
 155 .BR sched (7)