Re: [dpdk-dev] [PATCH] devtools/test-meson-builds: allow custom set of examples

[Thomas Monjalon <thomas@monjalon.net>]

09/11/2020 19:02, Bruce Richardson:
> On Mon, Nov 09, 2020 at 06:09:51PM +0100, Thomas Monjalon wrote:
> > 27/10/2020 18:38, Bruce Richardson:
> > > To test the installation process of DPDK using "ninja install"
> > > test-meson-builds.sh builds a subset of the examples using "make". To allow
> > > more flexibility for people testing, allow the set of examples chosen for
> > > this make test to be overridden using variable "DPDK_BUILD_TEST_EXAMPLES"
> > > in the environment.
> > > 
> > > Since a number of example apps link against drivers directly even for
> > > shared builds, we need to ensure that LD_LIBRARY_PATH points to the main
> > > DPDK lib folder so any dependencies of those drivers can be found e.g. that
> > > the PCI/vdev bus driver .so is found. [All drivers are symlinked from
> > > drivers dir back to lib dir on install, so only one dir rather than two is
> > > needed in the path.]
> > [...]
> > > +libdir=$(dirname $(find $DESTDIR -name librte_eal.so))
> > > +export LD_LIBRARY_PATH=$libdir:$LD_LIBRARY_PATH
> > 
> > I don't get why libdir is required for some examples,
> > and not for others? The pkg-config file is not enough?
> > 
> 
> It's only needed for examples that link against drivers directly. 
> 
> I believe it's needed in those cases, because app linker flags (including
> e.g. -lrte_pmd_bond) occur before the pkg-config flags, which means that
> the linker at that point does not have the path to find the dependencies of
> the driver. [In a normal build, this wouldn't be necessary because the
> library directory would be a standard path]

If it's just a matter of ordering,
it would be a better example to fix the ordering in the Makefile,
isn't it?