Re: [PATCH v3 1/1] eal: add C++ include guard in generic/rte_vect.h

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 4/7/2024 2:30 AM, Ashish Sadanandan wrote:
> 
> 
> On Wed, Apr 3, 2024 at 8:52 AM Thomas Monjalon <thomas@monjalon.net
> <mailto:thomas@monjalon.net>> wrote:
> 
>     02/04/2024 18:03, Ashish Sadanandan:
>     > Hi everyone,
>     > I've made the updates as suggested. Could someone please review
>     the latest
>     > patchset? Not sure if I followed the new patchset instructions
>     correctly,
>     > I've always had trouble with that part.
> 
>     I remember we were discussing about aligning all files.
>     I was waiting for a patch applying the rule we discussed.
> 
> I missed the part where people were volunteering me for additional work :)
> 
> The consensus seems to be that the extern "C" directives should only be
> in public headers, not private ones. Can you please tell me if there's
> an easy way to get a list of public headers? 
> 

Public headers are installed as part of ninja install target, so one
option is you can install a build to a custom folder and get the list
from there.
Or they are listed in meson.build files in 'headers' variable, you can
parse them.


Don't get confused with 'driver_sdk_headers' variable in meson files,
that is the list of headers required for driver development, and
installed if sdk ('enable_driver_sdk') meson option is enabled.

> 
>     > On Sun, Mar 17, 2024 at 8:44 PM Ashish Sadanandan <
>     > ashish.sadanandan@gmail.com <mailto:ashish.sadanandan@gmail.com>>
>     wrote:
>     >
>     > > The header was missing the extern "C" directive which causes name
>     > > mangling of functions by C++ compilers, leading to linker errors
>     > > complaining of undefined references to these functions.
>     > >
>     > > Also updated the coding style contribution guideline with a new
>     > > "Language Linkage" section stating `extern "C"` block should be
>     added to
>     > > public headers.
>     > >
>     > > Fixes: 86c743cf9140 ("eal: define generic vector types")
>     > > Cc: nelio.laranjeiro@6wind.com <mailto:nelio.laranjeiro@6wind.com>
>     > > Cc: stable@dpdk.org <mailto:stable@dpdk.org>
>     > >
>     > > Signed-off-by: Ashish Sadanandan <ashish.sadanandan@gmail.com
>     <mailto:ashish.sadanandan@gmail.com>>
>     > > ---
>     > >  .mailmap                                 |  2 +-
>     > >  doc/guides/contributing/coding_style.rst | 21 +++++++++++++++++++++
>     > >  lib/eal/include/generic/rte_vect.h       |  8 ++++++++
>     > >  3 files changed, 30 insertions(+), 1 deletion(-)
>     > >
>     > > --- a/doc/guides/contributing/coding_style.rst
>     > > +++ b/doc/guides/contributing/coding_style.rst
>     > > +Language Linkage
>     > > +~~~~~~~~~~~~~~~~
>     > > +
>     > > +Public headers should enclose all function and variable
>     declarations and
>     > > definitions in an ``extern "C"`` block to facilitate
>     interoperability with
>     > > C++.
>     > > +
>     > > +.. code-block:: c
>     > > +
>     > > +   #ifndef _FILE_H_
>     > > +   #define _FILE_H_
>     > > +
>     > > +   #ifdef __cplusplus
>     > > +   extern "C" {
>     > > +   #endif
>     > > +
>     > > +   /* Code */
>     > > +
>     > > +   #ifdef __cplusplus
>     > > +   }
>     > > +   #endif
>     > > +
>     > > +   #endif /* _FILE_H_ */
> 
>     This is not describing where the includes should be placed.
>      
> 
> Will address this along with the rest of the headers.
> 
> Regards,
> Ashish.