[oe] bitbake and OE opperation

[Tim Bird]

Not to belabor this, but I'm going to try to repeat
this stuff back, to make sure I understand.

Richard Purdie wrote:
>> There are the following lines - I don't know if they're related or not:
>>
>> addtask build after do_populate_staging
>> do_build = ""
>> do_build[func] = "1"
> 
> These are very much related, it defines that there is a build task (with
> an associated function which defaults to empty). It says this build task
> depends on a "populate_staging" task.

So this is similar to:

build: do_populate_staging

in a makefile.

>> Maybe I'm thinking procedurally, and this is all declarative, but where
>> the heck are the actual statements executed during a "build"?
> 
> Nothing is executed by "build" itself, the key is in the dependency on
> "populate_staging".
> 
In this case, since build has no actual
commands associated with it, it is like a PHONY target in
a makefile?

> They're not hardcoded, the sequence is made through the definition of
> tasks, each of which depend on each other. Very roughly:
> 
> build depends on populate_staging
> populate_staging depends on package_write
> package_write depends on package
> package depends on install
> install depends on compile
> compile depends on configure
> configure depends on patch
> patch depends on unpack
> unpack depends on fetch
>