Hi Robert, On Monday 11 November 2013 06:30:46 Robert P. J. Day wrote: > still slogging my way through the dev manual, and here: > > http://www.yoctoproject.org/docs/latest/dev-manual/dev-manual.html#usingpoky > -extend-customimage > > section 5.2.1 recommends that recipe files use: > > IMAGE_INSTALL += "strace" > > while, further down in section 5.2.4, developers are encouraged to add > to their personal local.conf: > > IMAGE_INSTALL_append = " strace"
There is a good reason for this difference - it's likely that IMAGE_INSTALL will be set using = in the image recipe, and thus if you use += to add to it in local.conf it will have no effect. _append on the other hand is deferred until later and thus it will always work from local.conf. In the image recipe it's OK to use IMAGE_INSTALL += because you'll be able to put it in the right place with regard to any other assignment of the variable. As I've noted more than once, modifying IMAGE_INSTALL or CORE_IMAGE_EXTRA_INSTALL from local.conf is really only appropriate for quick testing - for anything beyond that users should be creating their own image recipe(s). > is there somewhere in a yocto doc a clear explanation of the proper > usage of "+=" versus "_append"? because, in my experience, that's a > point of serious confusion for new users. The proper place for the general discussion about how these operators work is really the BitBake manual; we're planning on promoting that to a first-class citizen and publishing it with the rest of our manuals for 1.6. Cheers, Paul -- Paul Eggleton Intel Open Source Technology Centre _______________________________________________ yocto mailing list [email protected] https://lists.yoctoproject.org/listinfo/yocto
