Re: [PATCH v1 1/4] tools/rtla: Consolidate nr_cpus usage across all tools

[Crystal Wood <crwood@redhat.com>]

On Wed, 2025-12-17 at 10:06 +0100, Tomas Glozar wrote:
> út 16. 12. 2025 v 15:41 odesílatel Tomas Glozar <tglozar@redhat.com> napsal:
> > Since commit 2f3172f9dd58c ("tools/rtla: Consolidate code between
> > osnoise/timerlat and hist/top") that was merged into 6.18, common.h
> > includes timerlat_u.h. Your change thus causes a double include of
> > timerlat_u.h, leading to a build error:
> > 
> > In file included from src/timerlat_u.c:20:
> > src/timerlat_u.h:6:8: error: redefinition of ‘struct timerlat_u_params’
> >    6 | struct timerlat_u_params {
> >      |        ^~~~~~~~~~~~~~~~~
> > In file included from src/common.h:5,
> >                 from src/timerlat_u.c:19:
> > src/timerlat_u.h:6:8: note: originally defined here
> >    6 | struct timerlat_u_params {
> >      |        ^~~~~~~~~~~~~~~~~
> > 
> > Please rebase your patchset and fix this so that timerlat_u.h is only
> > included once.
> > 
> 
> Correction: the base of the patchset has nothing to do with this. It
> is the C standard, from C23 (default in GCC 15), redefinition of
> structs is allowed [1], so this error doesn't exist. In earlier
> standards, this is not allowed.
> 
> [1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2863.pdf

Regardless of how permissive the language might be getting in this case,
we should have #pragma once on all of the headers to avoid this sort of
problem.

-Crystal