1.\" Copyright 2014 Garrett D'Amore <garrett@damore.org> 2.\" Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved. 3.\" Copyright (c) 1980 Regents of the University of California. All rights reserved. The Berkeley software License Agreement specifies the terms and conditions for redistribution. 4.\" Portions Copyright (c) 1992, X/Open Company Limited All Rights Reserved. 5.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at 6.\" http://www.opengroup.org/bookstore/. 7.\" The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html. 8.\" This notice shall appear on any product containing this material. 9.Dd "Aug 16, 2014" 10.Dt USLEEP 3C 11.Os 12.Sh NAME 13.Nm usleep 14.Nd suspend execution for interval in microseconds 15.Sh SYNOPSIS 16.In unistd.h 17.Ft int 18.Fn usleep "useconds_t useconds" 19.Sh DESCRIPTION 20The 21.Fn usleep 22function suspends the caller from execution for the number 23of microseconds specified by the 24.Fa useconds 25argument. The actual suspension 26time might be less than requested because any caught signal will terminate 27.Fn usleep 28following execution of that signal's catching routine. The 29suspension time might be longer than requested by an arbitrary amount because 30of the scheduling of other activity in the system. 31.Lp 32If the value of 33.Fa useconds 34is 0, then the call has no effect. 35.Lp 36The use of the 37usleep 38function has no effect on the action or blockage 39of any signal. In a multithreaded process, only the invoking thread is 40suspended from execution. 41.Sh RETURN VALUES 42On completion, 43.Fn usleep 44returns 0. There are no error returns. 45.Sh ERRORS 46No errors are returned. 47.Sh USAGE 48The 49.Fn usleep 50function is included for its historical usage and is Obsolete. The 51.Xr nanosleep 3C 52function is preferred over this function. 53.Sh INTERFACE STABILITY 54.Sy Obsolete Standard . 55.Sh MT-LEVEL 56.Sy Safe . 57.Sh SEE ALSO 58.Xr nanosleep 3C , 59.Xr sleep 3C , 60.Xr unistd.h 3HEAD , 61.Xr standards 5 62.Sh STANDARDS 63The 64.Fn usleep 65function is available in the following compilation environments. See 66.Xr standards 5 . 67.Lp 68.Bl -bullet -compact 69.It 70.St -xpg4.2 71.It 72.St -susv2 73.It 74.St -susv3 75.El 76.Lp 77It is marked obsolete in 78.St -susv3 , and was removed from 79.St -p1003.1-2008 . 80