Re: [dpdk-dev] Proposal to add a new toolchain for dpdk: g++

[Neil Horman <nhorman@tuxdriver.com>]

On Tue, Feb 18, 2020 at 03:06:51PM +0100, Victor Huertas wrote:
> Thanks Neil for your answer,
> I think I will try the first option you posted without touching the
> makefiles from the dpdk-stable and I will tell how it goes.
> So, as a conclusion, it seems that all the modifications I have done are
> not necessary in order to build your DPDK application using g++.
> 
That should be correct, yes.  As Bruce noted, all of the exported header files
are wrapped as extern C, and so they should interface to c++ code, even when the
library is compiled with gcc.  If that doesn't work, thats a bug in DPDK.

Neil

> Regards,
> 
> El mar., 18 feb. 2020 a las 14:13, Neil Horman (<nhorman@tuxdriver.com>)
> escribió:
> 
> > On Mon, Feb 17, 2020 at 02:39:58PM +0000, Bruce Richardson wrote:
> > > On Mon, Feb 17, 2020 at 11:01:21AM +0100, Victor Huertas wrote:
> > > > Hi all,
> > > >
> > > > I am using DPDK development environment to develop an application from
> > > > which I have to access C++ code.
> > > > I managed to modify some internal mk files in the dpdk-stable
> > repository to
> > > > allow g++ compiler to be supported.
> > > >
> > > > I have all the modified files well identified and I wonder if the
> > support
> > > > team is interested to add this toolchain in future DPDK releases.
> > > >
> > > Rather than trying to build DPDK with g++, or to use the DPDK makefiles
> > > with your C++ application, can I recommend instead that you treat DPDK as
> > > any third-party library and build it independently of your application.
> > >
> > > If you compile and install DPDK using meson and ninja - or install the
> > > DPDK package from your linux distro - you will have a 'libdpdk.pc' file
> > > installed for use by pkg-config. Then for building your application, put
> > in
> > > the relevant calls to pkg-config i.e. 'pkg-config --cflags libdpdk' and
> > > 'pkg-config --libs libdpdk', into your app makefile and work from there.
> > >
> > yes, exactly this.  The proscribed method of handling issues like this is
> > to
> > either:
> >
> > 1) Build dpdk separately (or just install it from whatever distribution
> > you are
> > using, if thats an option), and just link against it (either statically or
> > dynamically) when you build your application.
> >
> > 2)  If you embed dpdk source in your
> > environment, and build it at the same time as your application, you should
> > interface to its build system, by just calling ninja/meson or make from a
> > build
> > target in your application - the dpdk build file should properly select gcc
> > instead of g++, which you should already have if you have g++ installed.
> >
> > Neil
> >
> > > Note too, that all DPDK header files should already be safe for inclusion
> > > in C++ code - if not, please log a bug.
> > >
> > > Regards,
> > > /Bruce
> > >
> >
> 
> 
> -- 
> Victor