sys/nanosleep.2

   1 .\" $FreeBSD: src/lib/libc/sys/nanosleep.2,v 1.8.2.4 2001/12/14 18:34:01 ru Exp $
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  36 .\"     @(#)sleep.3     8.1 (Berkeley) 6/4/93
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  38 .Dd April 17, 1997
  39 .Dt NANOSLEEP 2
  40 .Os
  41 .Sh NAME
  42 .Nm nanosleep
  43 .Nd suspend thread execution for an interval measured in nanoseconds
  44 .Sh LIBRARY
  45 .Lb libc
  46 .Sh SYNOPSIS
  47 .In time.h
  48 .Ft int
  49 .Fo nanosleep
  50 .Fa "const struct timespec *rqtp"
  51 .Fa "struct timespec *rmtp"
  52 .Fc
  53 .Sh DESCRIPTION
  54 The
  55 .Fn nanosleep
  56 function causes the calling thread to sleep
  57 for the amount of time specified in
  58 .Fa rqtp
  59 (the actual time slept may be longer, due to system latencies
  60 and possible limitations in the timer resolution of the hardware).
  61 An unmasked signal will
  62 cause
  63 .Fn nanosleep
  64 to terminate the sleep early, regardless of the
  65 .Dv SA_RESTART
  66 value on the interrupting signal.
  67 .Sh RETURN VALUES
  68 If
  69 .Fn nanosleep
  70 returns because the requested time has elapsed,
  71 the value returned will be zero.
  72 .Pp
  73 If
  74 .Fn nanosleep
  75 returns due to the delivery of a signal, the value returned
  76 will be the -1, and the global variable
  77 .Va errno
  78 will be set to indicate the interruption.
  79 If
  80 .Fa rmtp
  81 is
  82 .Pf non- Dv NULL ,
  83 the timespec structure it references is updated to contain the
  84 unslept amount (the request time minus the time actually slept).
  85 .Sh ERRORS
  86 The
  87 .Fn nanosleep
  88 call fails if:
  89 .Bl -tag -width Er
  90 .It Bq Er EFAULT
  91 Either
  92 .Fa rqtp
  93 or
  94 .Fa rmtp
  95 points to memory that is not a valid part of the process
  96 address space.
  97 .It Bq Er EINTR
  98 .Fn nanosleep
  99 was interrupted by the delivery of a signal.
 100 .It Bq Er EINVAL
 101 .Fa rqtp
 102 specified a nanosecond value less than zero
 103 or greater than or equal to 1000 million.
 104 .It Bq Er ENOSYS
 105 .Fn nanosleep
 106 is not supported by this implementation.
 107 .El
 108 .Sh SEE ALSO
 109 .Xr sigsuspend 2 ,
 110 .Xr sleep 3
 111 .Sh STANDARDS
 112 The
 113 .Fn nanosleep
 114 function conforms to
 115 .St -p1003.1b-93 .