gen/usleep.3

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