man3/sched_getcpu.3

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  26 .TH SCHED_GETCPU 3 2017-09-15 "Linux" "Linux Programmer's Manual"
  27 .SH NAME
  28 sched_getcpu \- determine CPU on which the calling thread is running
  29 .SH SYNOPSIS
  30 .nf
  31 .B #include <sched.h>
  32 .PP
  33 .B int sched_getcpu(void);
  34 .fi
  35 .PP
  36 .in -4n
  37 Feature Test Macro Requirements for glibc (see
  38 .BR feature_test_macros (7)):
  39 .in
  40 .PP
  41 .BR sched_getcpu ():
  42 .ad l
  43 .RS 4
  44 .PD 0
  45 .TP 4
  46 Since glibc 2.14:
  47 _GNU_SOURCE
  48 .TP 4
  49 Before glibc 2.14:
  50 _BSD_SOURCE || _SVID_SOURCE
  51     /* _GNU_SOURCE also suffices */
  52 .PD
  53 .RE
  54 .ad b
  55 .SH DESCRIPTION
  56 .BR sched_getcpu ()
  57 returns the number of the CPU on which the calling thread is currently executing.
  58 .SH RETURN VALUE
  59 On success,
  60 .BR sched_getcpu ()
  61 returns a nonnegative CPU number.
  62 On error, \-1 is returned and
  63 .I errno
  64 is set to indicate the error.
  65 .SH ERRORS
  66 .TP
  67 .B ENOSYS
  68 This kernel does not implement
  69 .BR getcpu (2).
  70 .SH VERSIONS
  71 This function is available since glibc 2.6.
  72 .SH ATTRIBUTES
  73 For an explanation of the terms used in this section, see
  74 .BR attributes (7).
  75 .TS
  76 allbox;
  77 lb lb lb
  78 l l l.
  79 Interface       Attribute       Value
  80 T{
  81 .BR sched_getcpu ()
  82 T}      Thread safety   MT-Safe
  83 .TE
  84 .SH CONFORMING TO
  85 .BR sched_getcpu ()
  86 is glibc-specific.
  87 .SH NOTES
  88 The call
  89 .PP
  90 .in +4n
  91 .EX
  92 cpu = sched_getcpu();
  93 .EE
  94 .in
  95 .PP
  96 is equivalent to the following
  97 .BR getcpu (2)
  98 call:
  99 .PP
 100 .in +4n
 101 .EX
 102 int c, s;
 103 s = getcpu(&c, NULL, NULL);
 104 cpu = (s == \-1) ? s : c;
 105 .EE
 106 .in
 107 .SH SEE ALSO
 108 .BR getcpu (2),
 109 .BR sched (7)