[dpdk-dev] JSON compilation in examples/vm_power_manager

[Thomas Monjalon]

01/11/2018 15:26, Hunt, David:
> Hi Thomas,
> 
> 
> On 1/11/2018 10:47 AM, Thomas Monjalon wrote:
> > Hi Dave,
> >
> > In examples/vm_power_manager/Makefile, jansson lib availability
> > is detected with pkg-config --exists.
> > As we have seen for telemetry lib, we can detect jansson
> > for the wrong arch and enable it no matter the arch being compiled.
> >
> > The solution was to disable it in Makefile and use meson for
> > reliable dependency detection.
> >
> > Would you like to do the same for this app?
> >
> >
> 
> I would prefer that if the user is cross compiling or selecting a 
> different target, that they
> set up their environment variables correctly for compilation. In this 
> case, the user should set
> PKG_CONFIG_LIBDIR to point to the relevant library folder, e.g. for an 
> i386 build:
> 
> export PKG_CONFIG_LIBDIR=/usr/lib/i386-linux-gnu/pkgconfig
> 
> That way the Makefile will pick up the correct library if it's present, 
> and build without the library
> if it is not present.
> 
> Also, if DPDK is being built natively on a machine, the makefile should 
> be fine as it is.
> 
> So, how about I create a patch to add a few lines to the docs around 
> compilation
> describing how to set up PKG_CONFIG_LIBDIR correctly for the 
> vm_power_manager
> sample app?

I think it was the solution I thought about for telemetry.
But in the case of multilib installation (x86_64/i686),
we do not have such separate directory.
I think the only reliable solution is to test compilation
as autotools or meson do.