unique id (uid, uuid, guid etc) class needed
in [C++]
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From: Andrew on 9 Dec 2009 21:03 Hello, I need a uuid class. After a bit of googling I see that at some point there was some work in boost for this but it looks like it will be a while before it is generally available. It is not in 1.41.1. Does anyone know if there is one available elsewhere? It must be portable of course. The project I am currently working on uses the UUID stuff from Microsoft (for RPC). I want to avoid such lock-in. uuids are quite tricky to implement from scratch. I tried to do it myself several years ago, using ideas from the uids in DCE. One of the problems is in efficiently generating random numbers with a large period. Plus, they have to be unique across machines where several processes on several machines may be generating them simulataneously. This will definately be the case for my app. I reckon this is why such uids often incorporate elements of the IP or MAC address. That's tricky to do in a portable and efficient way. Last time I did it I wound up having to interrogate the ethervard card using int86 (uurrgghh) on windows and using ioctl for solaris (eeuuggh). Regards, Andrew Marlow -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: George Neuner on 11 Dec 2009 03:16 On Thu, 10 Dec 2009 08:03:21 CST, Andrew <marlow.andrew(a)googlemail.com> wrote: >I need a uuid class. After a bit of googling I see that at some point >there was some work in boost for this but it looks like it will be a >while before it is generally available. It is not in 1.41.1. Does >anyone know if there is one available elsewhere? It must be portable >of course. The project I am currently working on uses the UUID stuff >from Microsoft (for RPC). I want to avoid such lock-in. I don't know offhand how portable it is, but the uuid implementation that is in Linux's EXT2/EXT3 filesystem is used by a number of systems that need global identifiers. See the e2fsprogs package. George -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Michael Oswald on 11 Dec 2009 05:21 > Content-Type: text/plain; charset=ISO-8859-1; format=flowed X-Original-Date: Fri, 11 Dec 2009 10:57:23 +0100 X-Submission-Address: c++-submit(a)netlab.cs.rpi.edu Hello Andrew, Andrew wrote: > Hello, > I need a uuid class. After a bit of googling I see that at some point > there was some work in boost for this but it looks like it will be a > while before it is generally available. It is not in 1.41.1. Does > anyone know if there is one available elsewhere? It must be portable > of course. The project I am currently working on uses the UUID stuff > from Microsoft (for RPC). I want to avoid such lock-in. You can have a look at Poco, which does have a portable UUID class. I don't know if it suits you, but you can have a look: http://pocoproject.org Just look under Documentation in the Foundation classes. lg, Michael -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Goran Pusic on 11 Dec 2009 05:22 > Content-Type: text/plain; charset=ISO-8859-1 X-Original-Date: Fri, 11 Dec 2009 03:32:07 -0800 (PST) X-Submission-Address: c++-submit(a)netlab.cs.rpi.edu On Dec 10, 3:03 pm, Andrew <marlow.and...(a)googlemail.com> wrote: > Hello, > > I need a uuid class. After a bit of googling I see that at some point > there was some work in boost for this but it looks like it will be a > while before it is generally available. It is not in 1.41.1. Does > anyone know if there is one available elsewhere? It must be portable > of course. The project I am currently working on uses the UUID stuff > from Microsoft (for RPC). I want to avoid such lock-in. > > uuids are quite tricky to implement from scratch. I tried to do it > myself several years ago, using ideas from the uids in DCE. One of the > problems is in efficiently generating random numbers with a large > period. Plus, they have to be unique across machines where several > processes on several machines may be generating them simulataneously. > This will definately be the case for my app. I reckon this is why such > uids often incorporate elements of the IP or MAC address. That's > tricky to do in a portable and efficient way. Last time I did it I > wound up having to interrogate the ethervard card using int86 > (uurrgghh) on windows and using ioctl for solaris (eeuuggh). > I wonder why do you need a class for that. Also, I'd be amazed that you have a target system where you want an UUID and that system doesn't already have function for that. It's certainly one call away on a Unix clone (uuid_generate) and Windows (CoCreateGUID). Goran. -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Joe Smith on 12 Dec 2009 04:44 "Andrew" <marlow.andrew(a)googlemail.com> wrote in message news:e8392674-e550-4625-9ca3-138a5d289c0e(a)c3g2000yqd.googlegroups.com... > Hello, > > I need a uuid class. After a bit of googling I see that at some point > there was some work in boost for this but it looks like it will be a > while before it is generally available. It is not in 1.41.1. Does > anyone know if there is one available elsewhere? It must be portable > of course. The project I am currently working on uses the UUID stuff > from Microsoft (for RPC). I want to avoid such lock-in. > > uuids are quite tricky to implement from scratch. I tried to do it > myself several years ago, using ideas from the uids in DCE. One of the > problems is in efficiently generating random numbers with a large > period. Plus, they have to be unique across machines where several > processes on several machines may be generating them simulataneously. > This will definately be the case for my app. I reckon this is why such > uids often incorporate elements of the IP or MAC address. That's > tricky to do in a portable and efficient way. Last time I did it I > wound up having to interrogate the ethervard card using int86 > (uurrgghh) on windows and using ioctl for solaris (eeuuggh). UUIDs have a very specific format to reduce the possibility of collision. Thus you should not be implementing them if you think they ever contain an IP address. (Hint they never do, but type A does use a MAC address). The only way to create valid UUIDs is standard C++ is to use the types bashed on hashing the name of the object. That in turn requires a universally unique name, such as a URN. Somewhat portable (i.e. portable to Windows, OS X, Linux, and perhaps some Unices) do exist, one that Wikipedia points out is the class in Qt. Otherwise, most of the rest of the solutions seem to be either Windows specific or POSIX-specific. -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
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