From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Veer To: andrew.lunn@ascom.ch Cc: ecos-discuss@sourceware.cygnus.com Subject: Re: [ECOS] serial_devio renamaed to cyg_serial_devio Date: Wed, 14 Jun 2000 07:26:00 -0000 Message-id: <200006141425.PAA18446@sheesh.cygnus.co.uk> References: <200006141218.OAA01603@biferten.ma.tech.ascom.ch> X-SW-Source: 2000-06/msg00142.html >>>>> "Andrew" == Andrew Lunn writes: >> I do not think there is any easy way of achieving this at >> present. Andrew> OK. Lets think about the future. The aim of using packages Andrew> is so that 3rd parties can develop there own packages Andrew> which can be plugged into the standard distribution. Andrew> Things change, move on, and are no longer compatible. As Andrew> this has shown you sometimes need the version information Andrew> to work out what to do to make things work with different Andrew> versions. Incompatible interface changes between versions, especially minor releases, should be avoided. The original name serial_devio was wrong, there should have been a prefix such as cyg_ in there from the beginning to reduce the possibility of name clashes. In practice getting all these things right takes time. Strictly speaking the serial renaming should have involved a major version upgrade, to V2.0, but we are not set up just yet to release core packages with different version numbers. Such functionality will be more and more important in future: it is quite likely that some packages, e.g. platform HAL's, will not change at all between core releases; there is no point in having separate installed versions x and y of a package when the two are identical. This will require enhancements to the release system and to the administration tools. However some way of coping with interface changes is desirable. Andrew> It seems to me there are two ways to do this, which are Andrew> not mutually exclusive. If there are big changes you Andrew> distribute multiple packages and let CDL work out the Andrew> dependances and pick the correct package to use. If the Andrew> changes are minor, as in this cause just one variable Andrew> name, #ifdef seems a good way to go. Agreed. >> What might be possible is for the configuration tools to generate >> additional #define's along the lines of: >> >> #define CYGPKG_IO_SERIAL v1_3_5 >> #define CYGPKG_IO_SERIAL_VERSION_MAJOR 1 >> #define CYGPKG_IO_SERIAL_VERSION_MINOR 3 >> ... Andrew> Sounds good. >> I am not quite sure what to call the versioning levels after major or >> minor, there could be any number of these. Andrew> CYGPKG_IO_SERIAL_VERSION_VERY_MINOR? You have to draw the Andrew> line somewhere. 3 levels seems enough to me. >> Also versions may include letters or text, e.g. 1.3.5beta Andrew> Specify that any trailling text are removed to leave an Andrew> integer? Andrew> So, do we need this sort of versioning features? Is this a Andrew> good approch? Unless somebody comes up with a better suggestion, or discovers a major flaw in this approach, I think something along these lines is worthwhile. I'll add it to the libcdl TODO list, which unfortunately is rather longer than I would like. If this is proving a major problem for you, and since Ascom is a paying customer, you may want to file a formal problem report to get its priority raised. Bart