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. 26The actual suspension time might be less than requested because any caught 27signal will terminate 28.Fn usleep 29following execution of that signal's catching routine. 30The suspension time might be longer than requested by an arbitrary amount 31because of the scheduling of other activity in the system. 32.Lp 33If the value of 34.Fa useconds 35is 0, then the call has no effect. 36.Lp 37The use of the 38usleep 39function has no effect on the action or blockage 40of any signal. 41In a multithreaded process, only the invoking thread is suspended from 42execution. 43.Sh RETURN VALUES 44On completion, 45.Fn usleep 46returns 0. 47There are no error returns. 48.Sh ERRORS 49No errors are returned. 50.Sh USAGE 51The 52.Fn usleep 53function is included for its historical usage and is Obsolete. 54The 55.Xr nanosleep 3C 56function is preferred over this function. 57.Sh INTERFACE STABILITY 58.Sy Obsolete Standard . 59.Sh MT-LEVEL 60.Sy Safe . 61.Sh SEE ALSO 62.Xr nanosleep 3C , 63.Xr sleep 3C , 64.Xr unistd.h 3HEAD , 65.Xr standards 5 66.Sh STANDARDS 67The 68.Fn usleep 69function is available in the following compilation environments. 70See 71.Xr standards 5 . 72.Lp 73.Bl -bullet -compact 74.It 75.St -xpg4.2 76.It 77.St -susv2 78.It 79.St -susv3 80.El 81.Lp 82It is marked obsolete in 83.St -susv3 , and was removed from 84.St -p1003.1-2008 . 85