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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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@(#)usleep.3 8.1 (Berkeley) 6/4/93
$FreeBSD$
.Dd February 13, 1998 .Dt USLEEP 3 .Os .Sh NAME .Nm usleep .Nd suspend process execution for an interval measured in microseconds .Sh LIBRARY .Lb libc .Sh SYNOPSIS n unistd.h .Ft int .Fn usleep "useconds_t microseconds" .Sh DESCRIPTION The .Fn usleep function suspends execution of the calling process until either .Fa microseconds microseconds have elapsed or a signal is delivered to the process and its action is to invoke a signal-catching function or to terminate the process. System activity may lengthen the sleep by an indeterminate amount.
The Regents of the University of California. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
4. Neither the name of the University nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
@(#)usleep.3 8.1 (Berkeley) 6/4/93
$FreeBSD$
.Dd February 13, 1998 .Dt USLEEP 3 .Os .Sh NAME .Nm usleep .Nd suspend process execution for an interval measured in microseconds .Sh LIBRARY .Lb libc .Sh SYNOPSIS n unistd.h .Ft int .Fn usleep "useconds_t microseconds" .Sh DESCRIPTION The .Fn usleep function suspends execution of the calling process until either .Fa microseconds microseconds have elapsed or a signal is delivered to the process and its action is to invoke a signal-catching function or to terminate the process. System activity may lengthen the sleep by an indeterminate amount.
p This function is implemented using .Xr nanosleep 2 by pausing for .Fa microseconds microseconds or until a signal occurs. Consequently, in this implementation, sleeping has no effect on the state of process timers, and there is no special handling for SIGALRM. .Sh RETURN VALUES .Rv -std usleep .Sh ERRORS The .Fn usleep function will fail if: l -tag -width Er t Bq Er EINTR A signal was delivered to the process and its action was to invoke a signal-catching function. .El .Sh SEE ALSO .Xr nanosleep 2 , .Xr sleep 3 .Sh HISTORY The .Fn usleep function appeared in x 4.3 .