Re: [v4l-utils v5 0/5] Add support for meson building

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Jun 16, 2021 at 04:59:47PM +0200, Mauro Carvalho Chehab wrote:
> Em Wed, 16 Jun 2021 11:26:10 -0300 Ariel D'Alessandro escreveu:
> 
> > Kieran,
> > 
> 
> > >  - Meson decided to default libdir to
> > >      /usr/local/lib/x86_64-linux-gnu
> > >    while autoconf used
> > >      /usr/local/lib
> > >    (it's likely handled by the package managers anyway)  
> > 
> >   $ meson configure ../build-meson/ | grep libdir
> >     libdir    lib/x86_64-linux-gnu    Library directory
> 
> The default isn't nice, and will likely cause troubles for the users, as 
> /usr/local/lib/x86_64-linux-gnu would hardly be at the ld.so.conf list of 
> paths for most people. So, when one would try to run a program, it will
> fail.

This depends on the distribution. On Debian-like distributions, to
enable multi-arch support, an arch-specific directory is used. Debian
adds it to ld.so.conf (for both /usr/lib and /usr/local/lib). On other
distributions, /usr/lib or /usr/lib64 will be used by meson.

> > As mentioned in another response. Autotools is building with `-g -O2` by
> > default, that'd the equivalent meson configuration option
> > --buildtype=debugoptimized. 
> 
> I can't understand the Meson's default... no optimization and no debug!
> Basically something that it is useless for both developers and for
> production. I wonder why they chose a crap default like that...

The default is debug, so it includes debug (and no optimization). This
can be overridden at the project level with

default_options : ['buildtype=debugoptimized']

in the project() function.

> > With this configuration the installtion
> > sizes are not that different:
> > 
> >   $ du -s installation_m*
> >   37068	installation_make
> >   37848	installation_meson
> 
> It sounds a lot more coherent.
> 
> > In this case the difference is related to libtool `.la` files not being
> > generated by meson and gconv/ only installed by meson. The latest is
> > probably a feature being only detected by meson in this case, will check
> > that out.
> 
> It was opted to not enable gconv by default, as similar patchset - needed
> to support ARIB STD B-24 charset used by Japanese digital TV - was sent to 
> gconv upstream (not sure if it was merged or not). On other words, the 
> contrib/gconv stuff is independent of v4l-utils itself: it basically
> adds an extra charset to be used by gconv upstream.
> 
> The only reason why it is present at v4l2-utils is that this charset
> is present on ISDB tables on TV broadcasts in Japan. The gconv library
> needs to support it, in order to  convert characters from MPEG tables
> to the system's charset.
> 
> Btw, that's basically one of the reasons why we print a summary of the
> options when ./configure runs.

-- 
Regards,

Laurent Pinchart