gen/usleep.3

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  28 .\"     @(#)usleep.3    8.1 (Berkeley) 6/4/93
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  31 .Dd February 13, 1998
  32 .Dt USLEEP 3
  33 .Os
  34 .Sh NAME
  35 .Nm usleep
  36 .Nd suspend thread execution for an interval measured in microseconds
  37 .Sh LIBRARY
  38 .Lb libc
  39 .Sh SYNOPSIS
  40 .In unistd.h
  41 .Ft int
  42 .Fo usleep
  43 .Fa "useconds_t useconds"
  44 .Fc
  45 .Sh DESCRIPTION
  46 The
  47 .Fn usleep
  48 function suspends execution of the calling thread until either
  49 .Fa useconds
  50 microseconds have elapsed
  51 or a signal is delivered to the thread whose action
  52 is to invoke a signal-catching function
  53 or to terminate the thread or process.
  54 The actual time slept may be longer, due to system latencies
  55 and possible limitations in the timer resolution of the hardware.
  56 .Pp
  57 This function is implemented, using
  58 .Xr nanosleep 2 ,
  59 by pausing for
  60 .Fa useconds
  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 .