minix/lib/libc/gen/usleep.3
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

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Groff

.\" $NetBSD: usleep.3,v 1.19 2010/04/29 17:29:56 jruoho Exp $
.\"
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.\" @(#)usleep.3 8.1 (Berkeley) 6/4/93
.\"
.Dd April 29, 2010
.Dt USLEEP 3
.Os
.Sh NAME
.Nm usleep
.Nd suspend execution for interval of microseconds
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn usleep "useconds_t microseconds"
.Sh DESCRIPTION
The
.Fn usleep
function
suspends execution of the calling process
until either the number of microseconds specified by
.Fa microseconds
have elapsed or a signal is delivered to the calling process and its
action is to invoke a signal catching function or to terminate the
process.
The suspension time may be longer than requested due to the
scheduling of other activity by the system.
.Pp
The
.Fa microseconds
argument must be less than 1,000,000.
If the value of
.Fa microseconds
is 0, then the call has no effect.
.Sh RETURN VALUES
On successful completion,
.Fn usleep
returns 0.
Otherwise, it returns \-1 and sets
.Va errno
to indicate the error.
.Sh ERRORS
The
.Fn usleep
function may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The
.Fa microseconds
interval specified 1,000,000 or more microseconds.
.El
.Sh SEE ALSO
.Xr nanosleep 2 ,
.Xr sleep 3
.Sh STANDARDS
The
.Fn usleep
function conforms to
.St -xpg4.2 .
It later appeared in the
.Tn POSIX
standard, but in
.St -p1003.1-2004
it was marked as legacy and the use of
.Xr nanosleep 2
was recommended instead.
The
.St -p1003.1-2008
revision removed
.Fn usleep
from the specification.
.Sh HISTORY
The
.Fn usleep
function appeared in
.Bx 4.3 .