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author | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
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committer | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
commit | be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da (patch) | |
tree | a18a706dffa5baf86a3b12bbfb4f81caa097f349 /lib/libc/gen/usleep.3 | |
parent | 2a27bd86e6002c871e3b5561a5334653bb222a77 (diff) | |
download | FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.zip FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.tar.gz |
BSD 4.4 Lite Lib Sources
Diffstat (limited to 'lib/libc/gen/usleep.3')
-rw-r--r-- | lib/libc/gen/usleep.3 | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/lib/libc/gen/usleep.3 b/lib/libc/gen/usleep.3 new file mode 100644 index 0000000..630e386 --- /dev/null +++ b/lib/libc/gen/usleep.3 @@ -0,0 +1,85 @@ +.\" Copyright (c) 1986, 1991, 1993 +.\" 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. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 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 +.\" +.Dd June 4, 1993 +.Dt USLEEP 3 +.Os BSD 4.3 +.Sh NAME +.Nm usleep +.Nd suspend execution for interval of microseconds +.Sh SYNOPSIS +.Fd #include <unistd.h> +.Ft void +.Fn usleep "u_int microseconds" +.Sh DESCRIPTION +The +.Fn usleep +function +suspends execution of the calling process +for +.Fa microseconds +of time. +System activity or time spent in processing the +call may lengthen the sleep slightly. +.Pp +If a timer is already running on the process its state is saved. +If the value +.Fa microseconds +is more than or equal to the remaining clock time for the saved timer, +the sleep time is set to +the remaining clock time. +The state of the previous timer +is restored after +.Fa microseconds +has passed. +.Pp +This routine is implemented using +.Xr setitimer 2 ; +it requires eight system calls each time it is invoked. +A similar but less compatible function can be obtained with a single +.Xr select 2 ; +such a function would not restart after signals, but would not interfere +with other uses of +.Xr setitimer . +.Sh SEE ALSO +.Xr setitimer 2 , +.Xr getitimer 2 , +.Xr sigpause 2 , +.Xr ualarm 3 , +.Xr sleep 3 , +.Xr alarm 3 +.Sh HISTORY +The +.Fn usleep +function appeared in +.Bx 4.3 . |