Re: [dpdk-dev] [PATCH v2 02/10] meson: add BUILDING_RTE_SDK

[Neil Horman <nhorman@tuxdriver.com>]

On Thu, Jun 13, 2019 at 03:44:02PM +0100, Bruce Richardson wrote:
> On Thu, Jun 13, 2019 at 10:23:36AM -0400, Neil Horman wrote:
> > The __rte_internal macro is defined dependent on the value of the build
> > environment variable BUILDING_RTE_SDK.  This variable was set in the
> > Makefile environment but not the meson environment, so lets reconcile
> > the two by defining it for meson in the lib and drivers directories, but
> > not the examples/apps directories, which should be treated as they are
> > not part of the core DPDK library
> > 
> > Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> > CC: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
> > CC: Bruce Richardson <bruce.richardson@intel.com>
> > CC: Thomas Monjalon <thomas@monjalon.net>
> > ---
> >  drivers/meson.build | 1 +
> >  lib/meson.build     | 1 +
> >  2 files changed, 2 insertions(+)
> > 
> > diff --git a/drivers/meson.build b/drivers/meson.build
> > index 4c444f495..a312277d1 100644
> > --- a/drivers/meson.build
> > +++ b/drivers/meson.build
> > @@ -23,6 +23,7 @@ endif
> >  
> >  # specify -D_GNU_SOURCE unconditionally
> >  default_cflags += '-D_GNU_SOURCE'
> > +default_cflags += '-DBUILDING_RTE_SDK'
> >  
> >  foreach class:dpdk_driver_classes
> >  	drivers = []
> > diff --git a/lib/meson.build b/lib/meson.build
> > index e067ce5ea..0e398d534 100644
> > --- a/lib/meson.build
> > +++ b/lib/meson.build
> > @@ -35,6 +35,7 @@ if is_windows
> >  endif
> >  
> >  default_cflags = machine_args
> > +default_cflags += '-DBUILDING_RTE_SDK'
> >  if cc.has_argument('-Wno-format-truncation')
> >  	default_cflags += '-Wno-format-truncation'
> >  endif
> 
> While this will work, it's not something that individual components should
> ever need to override so I think using "add_project_arguments()" function
> is a better way to add this to the C builds.
> 
That sounds like it makes sense to me, but reading the documentation for meson,
I'm not sure I see the behavioral difference.  Can you elaborate on how
add_project_arguments behaves differently here?

Neil

> add_project_arguments('-DBUILDING_RTE_SDK', language: 'c')
> 
> Ref: http://mesonbuild.com/Adding-arguments.html
> Ref: http://mesonbuild.com/Reference-manual.html#add_project_arguments
> 
> /Bruce
>