[yocto] Can any one please tell the what is the exact difference between DEPENDS and RDEPENDS

[Petter Mabäcker]

2015-10-08 06:37 skrev Vivek Per: 

> Hi, 
> Can any one please tell
the what is the exact difference between DEPENDS and RDEPENDS . I am not
able to get it . How these variables are exactly parsed. 
> 
> -regards

> vivek

Hi, 

I guess you already have read through the manual about
the variables?


http://www.yoctoproject.org/docs/1.8/ref-manual/ref-manual.html#var-RDEPENDS


http://www.yoctoproject.org/docs/1.8/ref-manual/ref-manual.html#var-DEPENDS


The overall description of the differences are (please someone
correct me if you find my answer incorrect) that DEPENDS specifics
build-time dependencies (e.i. other recipe files) so you should be
guaranteed that all packages listed in the DEPENDS has been built and
installed in the sysroot before your new package starts its configure
task. 

RDEPENDS on the other hand, is a run-time dependency so instead
of other recipe files RDEPENDS lists packages that should have been
installed in order to correctly run your package on target. 

All this
is explained more in detail in the manual (see above links). Also keep
in mind that DEPENDS works with recipes and RDEPENDS with packages
(which isn't necessary the same). Debug the PACKAGES for a specific
variable
(http://www.yoctoproject.org/docs/1.8/ref-manual/ref-manual.html#var-PACKAGES)
in order to get a clue about what packages a recipe will generate. 

If
you still have a hard to understanding the differences my suggestion is
that you starts playing around a bit with them. Create a project and add
some DEPENDS and RDEPENDS to a recipe(s), build the affected packages
and investigate if they have been built in the expected order. This can
for example be verified by tracking the build output or by looking
through the cooker logs tmp/log/cooker/*. 

BR Petter 

Petter
Mabäcker

Technux <petter at technux.se>
www.technux.se
 
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