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freebsd-nq/bin/uuidgen/uuidgen.1

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Add uuidgen(2) and uuidgen(1). The uuidgen command, by means of the uuidgen syscall, generates one or more Universally Unique Identifiers compatible with OSF/DCE 1.1 version 1 UUIDs. From the Perforce logs (change 11995): Round of cleanups: o Give uuidgen() the correct prototype in syscalls.master o Define struct uuid according to DCE 1.1 in sys/uuid.h o Use struct uuid instead of uuid_t. The latter is defined in sys/uuid.h but should not be used in kernel land. o Add snprintf_uuid(), printf_uuid() and sbuf_printf_uuid() to kern_uuid.c for use in the kernel (currently geom_gpt.c). o Rename the non-standard struct uuid in kern/kern_uuid.c to struct uuid_private and give it a slightly better definition for better byte-order handling. See below. o In sys/gpt.h, fix the broken uuid definitions to match the now compliant struct uuid definition. See below. o In usr.bin/uuidgen/uuidgen.c catch up with struct uuid change. A note about byte-order: The standard failed to provide a non-conflicting and unambiguous definition for the binary representation. My initial implementation always wrote the timestamp as a 64-bit little-endian (2s-complement) integral. The clock sequence was always written as a 16-bit big-endian (2s-complement) integral. After a good nights sleep and couple of Pan Galactic Gargle Blasters (not necessarily in that order :-) I reread the spec and came to the conclusion that the time fields are always written in the native by order, provided the the low, mid and hi chopping still occurs. The spec mentions that you "might need to swap bytes if you talk to a machine that has a different byte-order". The clock sequence is always written in big-endian order (as is the IEEE 802 address) because its division is resulting in bytes, making the ordering unambiguous.
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.\" Copyright (c) 2002 Marcel Moolenaar
.\" 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.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
.\"
.\" $FreeBSD$
.\"
.Dd May 23, 2002
.Dt UUIDGEN 1
.Os
.Sh NAME
.Nm uuidgen
.Nd generate universally unique identifiers
.Sh SYNOPSIS
.Nm
.Op Fl 1
.Op Fl n Ar count
.Sh DESCRIPTION
The
.Nm
utility by default generates a single universally unique identifier (UUID),
mdoc(7) police: kill hard sentence breaks.
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also known as a globally unique identifier (GUID).
The UUID is written to stdout.
The following options can be used to change the number of identifiers
Add uuidgen(2) and uuidgen(1). The uuidgen command, by means of the uuidgen syscall, generates one or more Universally Unique Identifiers compatible with OSF/DCE 1.1 version 1 UUIDs. From the Perforce logs (change 11995): Round of cleanups: o Give uuidgen() the correct prototype in syscalls.master o Define struct uuid according to DCE 1.1 in sys/uuid.h o Use struct uuid instead of uuid_t. The latter is defined in sys/uuid.h but should not be used in kernel land. o Add snprintf_uuid(), printf_uuid() and sbuf_printf_uuid() to kern_uuid.c for use in the kernel (currently geom_gpt.c). o Rename the non-standard struct uuid in kern/kern_uuid.c to struct uuid_private and give it a slightly better definition for better byte-order handling. See below. o In sys/gpt.h, fix the broken uuid definitions to match the now compliant struct uuid definition. See below. o In usr.bin/uuidgen/uuidgen.c catch up with struct uuid change. A note about byte-order: The standard failed to provide a non-conflicting and unambiguous definition for the binary representation. My initial implementation always wrote the timestamp as a 64-bit little-endian (2s-complement) integral. The clock sequence was always written as a 16-bit big-endian (2s-complement) integral. After a good nights sleep and couple of Pan Galactic Gargle Blasters (not necessarily in that order :-) I reread the spec and came to the conclusion that the time fields are always written in the native by order, provided the the low, mid and hi chopping still occurs. The spec mentions that you "might need to swap bytes if you talk to a machine that has a different byte-order". The clock sequence is always written in big-endian order (as is the IEEE 802 address) because its division is resulting in bytes, making the ordering unambiguous.
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and the method used:
.Bl -tag -width indent
.It Fl 1
This option only has effect if multiple identifiers are to be generated and
instructs
.Nm
to not generate them in batch, but one at a time.
.It Fl n
mdoc(7) police: kill hard sentence breaks.
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This option controls the number of identifiers generated.
By default, multiple
Add uuidgen(2) and uuidgen(1). The uuidgen command, by means of the uuidgen syscall, generates one or more Universally Unique Identifiers compatible with OSF/DCE 1.1 version 1 UUIDs. From the Perforce logs (change 11995): Round of cleanups: o Give uuidgen() the correct prototype in syscalls.master o Define struct uuid according to DCE 1.1 in sys/uuid.h o Use struct uuid instead of uuid_t. The latter is defined in sys/uuid.h but should not be used in kernel land. o Add snprintf_uuid(), printf_uuid() and sbuf_printf_uuid() to kern_uuid.c for use in the kernel (currently geom_gpt.c). o Rename the non-standard struct uuid in kern/kern_uuid.c to struct uuid_private and give it a slightly better definition for better byte-order handling. See below. o In sys/gpt.h, fix the broken uuid definitions to match the now compliant struct uuid definition. See below. o In usr.bin/uuidgen/uuidgen.c catch up with struct uuid change. A note about byte-order: The standard failed to provide a non-conflicting and unambiguous definition for the binary representation. My initial implementation always wrote the timestamp as a 64-bit little-endian (2s-complement) integral. The clock sequence was always written as a 16-bit big-endian (2s-complement) integral. After a good nights sleep and couple of Pan Galactic Gargle Blasters (not necessarily in that order :-) I reread the spec and came to the conclusion that the time fields are always written in the native by order, provided the the low, mid and hi chopping still occurs. The spec mentions that you "might need to swap bytes if you talk to a machine that has a different byte-order". The clock sequence is always written in big-endian order (as is the IEEE 802 address) because its division is resulting in bytes, making the ordering unambiguous.
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identifiers are generated in batch.
.El
.Pp
Batched generation yields a dense set of identifiers in such a way that there
is no identifier that is larger than the smallest identifier in the set and
smaller than the largest identifier in the set and that is not already in the
set.
.Pp
When generating the identifiers one at a time, the identifiers will be close
to each other, but operating system latency and processing time will be
reflected in the distance between two successive identifiers.
.Sh DIAGNOSTICS
.Ex -std
.Sh SEE ALSO
.Xr uuidgen 2
.Sh HISTORY
The
.Nm
command first appeared in
.Fx 5.0 .
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