[PATCH] Avoid clang warnings in fwd.h

[PATCH] Avoid clang warnings in fwd.h

[Peter Foley]

e.g.
./fwd.h:65:63: warning: '_Static_assert' with no message is a C23 extension [-Wc23-extensions]
   65 | static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));

Signed-off-by: Peter Foley <pefoley@google.com>
---
 fwd.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fwd.h b/fwd.h
index 1607011..7d299b6 100644
--- a/fwd.h
+++ b/fwd.h
@@ -62,7 +62,7 @@ union fwd_listen_ref {
 	};
 	uint32_t u32;
 };
-static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
+static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t), "");
 
 enum fwd_ports_mode {
 	FWD_UNSET = 0,
-- 
2.53.0.371.g1d285c8824-goog

Re: [PATCH] Avoid clang warnings in fwd.h

[David Gibson]

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On Mon, Feb 23, 2026 at 12:29:20PM -0500, Peter Foley wrote:
> e.g.
> ./fwd.h:65:63: warning: '_Static_assert' with no message is a C23 extension [-Wc23-extensions]
>    65 | static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> 
> Signed-off-by: Peter Foley <pefoley@google.com>
> ---
>  fwd.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fwd.h b/fwd.h
> index 1607011..7d299b6 100644
> --- a/fwd.h
> +++ b/fwd.h
> @@ -62,7 +62,7 @@ union fwd_listen_ref {
>  	};
>  	uint32_t u32;
>  };
> -static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> +static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t), "");

I'd prefer to see an actual message added here, rather than just
minimally suppressing the warning.

>  
>  enum fwd_ports_mode {
>  	FWD_UNSET = 0,
> -- 
> 2.53.0.371.g1d285c8824-goog
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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Re: [PATCH] Avoid clang warnings in fwd.h

[Stefano Brivio]

On Tue, 24 Feb 2026 16:48:14 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Mon, Feb 23, 2026 at 12:29:20PM -0500, Peter Foley wrote:
> > e.g.
> > ./fwd.h:65:63: warning: '_Static_assert' with no message is a C23 extension [-Wc23-extensions]
> >    65 | static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> > 
> > Signed-off-by: Peter Foley <pefoley@google.com>
> > ---
> >  fwd.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fwd.h b/fwd.h
> > index 1607011..7d299b6 100644
> > --- a/fwd.h
> > +++ b/fwd.h
> > @@ -62,7 +62,7 @@ union fwd_listen_ref {
> >  	};
> >  	uint32_t u32;
> >  };
> > -static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> > +static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t), "");  
> 
> I'd prefer to see an actual message added here, rather than just
> minimally suppressing the warning.

Can you please suggest a message then? You added this static_assert()
in the first place.

-- 
Stefano

Re: [PATCH] Avoid clang warnings in fwd.h

[David Gibson]

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On Tue, Feb 24, 2026 at 09:50:56AM +0100, Stefano Brivio wrote:
> On Tue, 24 Feb 2026 16:48:14 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > On Mon, Feb 23, 2026 at 12:29:20PM -0500, Peter Foley wrote:
> > > e.g.
> > > ./fwd.h:65:63: warning: '_Static_assert' with no message is a C23 extension [-Wc23-extensions]
> > >    65 | static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> > > 
> > > Signed-off-by: Peter Foley <pefoley@google.com>
> > > ---
> > >  fwd.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/fwd.h b/fwd.h
> > > index 1607011..7d299b6 100644
> > > --- a/fwd.h
> > > +++ b/fwd.h
> > > @@ -62,7 +62,7 @@ union fwd_listen_ref {
> > >  	};
> > >  	uint32_t u32;
> > >  };
> > > -static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> > > +static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t), "");  
> > 
> > I'd prefer to see an actual message added here, rather than just
> > minimally suppressing the warning.
> 
> Can you please suggest a message then? You added this static_assert()
> in the first place.

Fair point.

I looked into this, and realised that I can make another cleanup in
the vicinity which changes the union into a struct and makes this
static_assert() redundant amongst some other improvements.  Patch on
the list.

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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Re: [PATCH] Avoid clang warnings in fwd.h

[Stefano Brivio]

On Mon, 23 Feb 2026 12:29:20 -0500
Peter Foley <pefoley@google.com> wrote:

> e.g.
> ./fwd.h:65:63: warning: '_Static_assert' with no message is a C23 extension [-Wc23-extensions]
>    65 | static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> 
> Signed-off-by: Peter Foley <pefoley@google.com>
> ---
>  fwd.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fwd.h b/fwd.h
> index 1607011..7d299b6 100644
> --- a/fwd.h
> +++ b/fwd.h
> @@ -62,7 +62,7 @@ union fwd_listen_ref {
>  	};
>  	uint32_t u32;
>  };
> -static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t));
> +static_assert(sizeof(union fwd_listen_ref) == sizeof(uint32_t), "");
>  
>  enum fwd_ports_mode {
>  	FWD_UNSET = 0,

Peter, unless you see a problem with that, this patch would be
superseded by:

  [PATCH 2/3] fwd, pif: Replace with pif_sock_l4() with pif_listen()
  https://archives.passt.top/passt-dev/20260302043135.800803-3-david@gibson.dropbear.id.au/

as it avoids the need for this static_assert() altogether. So I would
drop this patch (carrying a Reported-by: tag) in favour of that one.

-- 
Stefano

Re: [PATCH] Avoid clang warnings in fwd.h

[Peter Foley]

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On Tue, Mar 3, 2026 at 2:11 PM Stefano Brivio <sbrivio@redhat.com> wrote:

>
> Peter, unless you see a problem with that, this patch would be
> superseded by:
>
>   [PATCH 2/3] fwd, pif: Replace with pif_sock_l4() with pif_listen()
>
> https://archives.passt.top/passt-dev/20260302043135.800803-3-david@gibson.dropbear.id.au/
>
> as it avoids the need for this static_assert() altogether. So I would
> drop this patch (carrying a Reported-by: tag) in favour of that one.
>

Sounds good, I'm mostly concerned with having a warning-free clang build.
The specific fix doesn't particularly matter.

Thanks,

Peter

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