gen/FreeBSD/usleep.3

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  32 .\"     @(#)usleep.3    8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/usleep.3,v 1.18 2002/12/29 00:59:09 mike Exp $
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  35 .Dd February 13, 1998
  36 .Dt USLEEP 3
  37 .Os
  38 .Sh NAME
  39 .Nm usleep
  40 .Nd suspend process execution for an interval measured in microseconds
  41 .Sh LIBRARY
  42 .Lb libc
  43 .Sh SYNOPSIS
  44 .In unistd.h
  45 .Ft int
  46 .Fn usleep "useconds_t microseconds"
  47 .Sh DESCRIPTION
  48 The
  49 .Fn usleep
  50 function suspends execution of the calling process until either
  51 .Fa microseconds
  52 microseconds have elapsed or a signal is delivered to the process and its
  53 action is to invoke a signal-catching function or to terminate the
  54 process.
  55 System activity may lengthen the sleep by an indeterminate amount.
  56 .Pp
  57 This function is implemented using
  58 .Xr nanosleep 2
  59 by pausing for
  60 .Fa microseconds
  61 microseconds or until a signal occurs.
  62 Consequently, in this implementation,
  63 sleeping has no effect on the state of process timers,
  64 and there is no special handling for SIGALRM.
  65 .Sh RETURN VALUES
  66 .Rv -std usleep
  67 .Sh ERRORS
  68 The
  69 .Fn usleep
  70 function
  71 will fail if:
  72 .Bl -tag -width Er
  73 .It Bq Er EINTR
  74 A signal was delivered to the process and its
  75 action was to invoke a signal-catching function.
  76 .El
  77 .Sh SEE ALSO
  78 .Xr nanosleep 2 ,
  79 .Xr sleep 3
  80 .Sh HISTORY
  81 The
  82 .Fn usleep
  83 function appeared in
  84 .Bx 4.3 .