[libcamera-devel] [PATCH] README: Add 'ldconfig' note

[Kieran Bingham]

Quoting Laurent Pinchart (2023-05-24 15:33:43)
> On Wed, May 24, 2023 at 03:16:42PM +0100, Kieran Bingham wrote:
> > Quoting Laurent Pinchart (2023-05-24 14:03:24)
> > > On Wed, May 24, 2023 at 02:50:53PM +0200, Jacopo Mondi via libcamera-devel wrote:
> > > > On Tue, May 23, 2023 at 12:25:30PM +0100, Kieran Bingham via libcamera-devel wrote:
> > > > > Provide an update in the README.rst to reflect that a first install may
> > > > > require a manual call to 'ldconfig' as the root user.
> > > > >
> > > > > Meson install does not do this.
> > > > 
> > > > Nothing specific about libcamera here, but I guess it doesn't hurt
> > > > 
> > > > Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> > > > 
> > > > > Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> > > > > ---
> > > > >  README.rst | 18 ++++++++++++++++++
> > > > >  1 file changed, 18 insertions(+)
> > > > >
> > > > > diff --git a/README.rst b/README.rst
> > > > > index 34b6b49f3575..48629280a936 100644
> > > > > --- a/README.rst
> > > > > +++ b/README.rst
> > > > > @@ -37,6 +37,24 @@ To fetch the sources, build and install:
> > > > >    meson setup build
> > > > >    ninja -C build install
> > > > >
> > > > > +
> > > > > +First run
> > > > > +~~~~~~~~~
> > > > > +
> > > > > +For a first install, or an install with a newer library version the linker
> > > > > +configuration may need to be updated. If you experience any error such as :
> > > 
> > > Extra space before colon.
> > > 
> > > > > +
> > > > > +::
> > > > > +
> > > > > +   cam: error while loading shared libraries: libcamera.so.0.0.4: cannot open shared object file: No such file or directory
> > > > > +
> > > > > +please run:
> > > > > +
> > > > > +::
> > > > > +
> > > > > +  sudo ldconfig
> > > 
> > > As Jacopo said, this isn't specific to libcamera, but I suppose it
> > > doesn't hurt. I hope the next step won't be to document how to add a
> > > custom directory to /etc/ld.so.conf, as your README.rst shouldn't become
> > > a Linux 101 tutorial :-)
> > 
> > Sure but then you could say why do we bother documenting how to run
> > 'meson' and 'ninja' ... It *is* specific to /running/ libcamera.
> > 
> > The reason for this is because users are confused [0]. For a while it
> > was required, then meson handled it ... now it doesn't anymore.
> > 
> > I'd put a:
> > 
> > Suggested-by: Brad Morgan <>
> > 
> > But I don't have a full address
> > 
> > [0] https://github.com/kbingham/libcamera/issues/70
> 
> Maybe we'll need a FAQ at some point to answer miscellaneous questions,
> to ensure the README.rst won't grow out of control.

I interpret your lack of positivity in this review as a nack.

But as you've seen - this is turning into a frequently asked question.

We have an FAQ on libcamera.org - but I don't think this is an
appropriate place for that. The issue occurs when following the
instructions we provide for installation from source.

I believe it would be better to fully document all the steps required to
be able to install /and use/ from source. (i.e. merge this patch)

--
Kieran

> 
> > > > > +
> > > > > +
> > > > >  Dependencies
> > > > >  ~~~~~~~~~~~~
> > > > >
> 
> -- 
> Regards,
> 
> Laurent Pinchart