[Buildroot] [PATCH 05/13] docs/manual: add section about dependency graphs

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2014-02-23 16:04 +0100, Thomas Petazzoni spake thusly:
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> ---
>  docs/manual/common-usage.txt | 52 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/docs/manual/common-usage.txt b/docs/manual/common-usage.txt
> index 9a8c92a..bef42c6 100644
> --- a/docs/manual/common-usage.txt
> +++ b/docs/manual/common-usage.txt
> @@ -149,3 +149,55 @@ of an ext2 filesystem may be corrupted; or, if you have sparse files in
>  your filesystem, those parts may not be all-zeroes when read back). You
>  should only use sparse files when handling files on the build machine, not
>  when transferring them to an actual device that will be used on the target.
> +
> +Graphing the dependencies between packages
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +[[graph-depends]]
> +
> +One of Buildroot's jobs is to know the dependencies between packages,
> +and make sure they are built in the right order. These dependencies
> +can sometimes be quite complicated, and for a given system, it is
> +often not easy to understand why such or such package was brought into
> +the build by Buildroot.
> +
> +In order to help understanding the dependencies, and therefore better
> +understand what is the role of the different components in your
> +embedded Linux system, Buildroot is capable of generating dependency
> +graphs.
> +
> +To generate a dependency graph of the full system you have compiled,
> +simply run:
> +
> +------------------------
> +make graph-depends
> +------------------------
> +
> +You will find the generated graph in
> ++output/graphs/graph-depends.pdf+.
> +
> +If your system is quite large, the dependency graph may be too complex
> +and difficult to read. It is therefore possible to generate the
> +dependency graph just for a given package:
> +
> +------------------------
> +make <pkg>-graph-depends
> +------------------------
> +
> +You will find the generated graph in
> ++output/graph/<pkg>-graph-depends.pdf+.
> +
> +Note that the dependency graphs are generated using the +dot+ tool
> +from the _Graphviz_ project, which you must have installed on your
> +system to use this feature. In most distributions, it is available as
> +the +graphviz+ package.
> +
> +By default, the dependency graphs are generated in the PDF
> +format. However, by passing the +GRAPH_OUT+ environment variable, you
> +can switch to other output formats, such as PNG, PostScript or
> +SVG. All formats supported by the +-T+ option of the +dot+ tool are
> +supported.
> +
> +--------------------------------
> +GRAPH_OUT=svg make graph-depends
> +--------------------------------
> -- 
> 1.8.3.2
> 
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> http://lists.busybox.net/mailman/listinfo/buildroot

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