On Tue, Dec 18, 2012 at 7:28 AM, Biao <huanmat...@163.com> wrote: > > At 2012-12-17 23:37:52,"Eren Türkay" <e...@hambedded.org> wrote: > >On Mon, Dec 17, 2012 at 05:06:26PM +0800, Biao wrote: > >> Greetings, > >> > >> I am a newbie tying to understand how bitbake works. > >> There is one line as BBPATH = "${TOPDIR}" in the > >> mybuild/conf/bblayers.conf, i would like to know where the TOPDIR is > >> defined? > > > >It's defind in "lib/bb/parse/parse_py/ConfHandler.py:36". When TOPDIR is > >not defined in any of the bitbake configuration files, it's set to > >current working directory automatically. > > > > The whole picture of how bitbake works is missing from the Manual of the > bitbake, which typically should be(I guess) : > > 1. Set some environment variables like "TOPDIR, THISDIR..." > > > 2. Looking for and parsing the conf/bblayers.conf. > > 3. Set the LAYERDIR and parsing each of the ONELAYER/conf/layer.conf > > 4. Locate and parsing the conf/bitbake.conf. > > 5. Go over of each of the .bb and setup all the global variables to get a > dependency tree... > > 6. Start the build > > 7.... > > Have a look at the Bitbake section of the Yocto Project Reference manual (Chapter 6), as it provides a little more information.
I am trying to draw a picture like the list above,which is from the bitbake's point of view, > > some of the list is not right, since lots things are still not clear to me. > If someone could draw such picture, it helps a lot to understand the bitbake. > > >(...) > > > >def init(data): > > topdir = data.getVar('TOPDIR') > > if not topdir: > > data.setVar('TOPDIR', os.getcwd()) > > > >(...) > > > >You may want to read the newly-written documentation about bitbake and > >open embedded. I tried to explain how things fit together. I would like > >to have your feedback. > > > >http://hambedded.org/blog/2012/11/24/from-bitbake-hello-world-to-an-image/ > > I will try to give some feedback after finishing the reading. > > But for now, there are some silly questions: > > 1. There is a base_do_fetch() {}, I did not find the explanation of the > keyword of 'base' in the manual, do i miss something? > > 2. There is 'bb.note' and 'bbnote' in the code example, is it a type-mistake > or something else? > > > > >-- > > . 73! DE TA1AET > > http://linkedin.com/in/erenturkay > > > _______________________________________________ > yocto mailing list > yocto@yoctoproject.org > https://lists.yoctoproject.org/listinfo/yocto > >
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