[EXT] Re: [PATCH 1/1] build: update link args and includes for libarchive

[Srikanth Yalavarthi]

> -----Original Message-----
> From: Bruce Richardson <bruce.richardson at intel.com>
> Sent: 23 October 2023 17:24
> To: Srikanth Yalavarthi <syalavarthi at marvell.com>
> Cc: Aaron Conole <aconole at redhat.com>; Igor Russkikh
> <irusskikh at marvell.com>; David Marchand <david.marchand at redhat.com>;
> dev at dpdk.org; Shivah Shankar Shankar Narayan Rao
> <sshankarnara at marvell.com>; Jerin Jacob Kollanukkaran
> <jerinj at marvell.com>; stable at dpdk.org
> Subject: Re: [EXT] Re: [PATCH 1/1] build: update link args and includes for
> libarchive
> 
> On Mon, Oct 23, 2023 at 11:40:14AM +0000, Srikanth Yalavarthi wrote:
> > > -----Original Message-----
> > > From: Bruce Richardson <bruce.richardson at intel.com>
> > > Sent: 23 October 2023 14:56
> > > To: Srikanth Yalavarthi <syalavarthi at marvell.com>
> > > Cc: Aaron Conole <aconole at redhat.com>; Igor Russkikh
> > > <irusskikh at marvell.com>; David Marchand
> <david.marchand at redhat.com>;
> > > dev at dpdk.org; Shivah Shankar Shankar Narayan Rao
> > > <sshankarnara at marvell.com>; Jerin Jacob Kollanukkaran
> > > <jerinj at marvell.com>; stable at dpdk.org
> > > Subject: [EXT] Re: [PATCH 1/1] build: update link args and includes
> > > for libarchive
> > >
> > > External Email
> > >
> > > --------------------------------------------------------------------
> > > -- On Fri, Oct 20, 2023 at 10:01:35AM -0700, Srikanth Yalavarthi
> > > wrote:
> > > > In order to avoid linking with all libraries listed as
> > > > Libs.private in libarchive.pc, libarchive is not added to ext_deps during
> meson setup.
> > > >
> > > > Since libarchive is not added to ext_deps, cross-compilation or
> > > > native compilation with libarchive installed in non-standard
> > > > location fails with errors related to "cannot find -larchive"
> > > > or "archive.h: No such file or directory". In order to fix the
> > > > build failures, user is required to define the 'c_args' and 'c_link_args'
> > > > with '-I<includedir>' and '-L<libdir>'.
> > > >
> > > > This patch updates meson build files to add libarchive's
> > > > includedir and libdir to compiler flags and would not require
> > > > setting c_args and c_link_args externally.
> > > >
> > > > Fixes: 40edb9c0d36b ("eal: handle compressed firmware")
> > > > Cc: stable at dpdk.org
> > > >
> > > > Signed-off-by: Srikanth Yalavarthi <syalavarthi at marvell.com>
> > > > ---
> > >
> > > Checking back through the mail archives I'm still a little unclear
> > > as to what breaks when we try using libarchive as any other package
> > > with a pkg-config file? I would have thought the best solution was
> > > just to add libarchive as an external dependency, found using
> > > pkg-config, to EAL. When we add it as a dependency, rather than
> > > using c/ldflags, we should get all this path fixup for free?
> > > Can you clarify what breaks when we add libarchive as a libeal
> > > dependency only?
> >
> > Below is my observation.
> >
> > In current implementation, we are looking for libarchive's availability
> through pkg-config.
> > When found, we are setting RTE_HAS_LIBARCHIVE=1 and adding '-larchive'
> to ldflags.
> >
> > Since, we are not adding libarchive to ext_deps (to avoid linking with
> > deps.private), the
> 
> This is the bit I'm a bit stuck on. What is the issues with adding libarchive to
> ext_deps? For other libs, when doing static builds we have to link with
> deps.private and it's the correct behaviour AFAIK. Not doing so would surely
> lead to problematic builds, no?

I agree on adding to ext_deps as it's the correct behaviour.

However, there was a discussion in mail archives regarding this.
https://inbox.dpdk.org/dev/20210605004024.660267a1@sovereign/

Adding Dmitry Kozlyuk for comments.

> 
> /Bruce