[Bug c++/106486] New: C++ warning for -Wmissing-prototypes is pure nuisance

[Bug c++/106486] New: C++ warning for -Wmissing-prototypes is pure nuisance

[hpa at zytor dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106486

            Bug ID: 106486
           Summary: C++ warning for -Wmissing-prototypes is pure nuisance
           Product: gcc
           Version: 12.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hpa at zytor dot com
  Target Milestone: ---

Since upgrading to gcc 12.1.1, I keep getting the following warning through
various projects:

cc1plus: warning: command-line option ‘-Wmissing-prototypes’ is valid for
C/ObjC but not for C++

This warning is pure nuisance. In a mixed-language project it is *extra*
important that the right prototypes are used, and it is far easier to enable
-Wmissing-prototypes project wide. This warning implies that one would have to
conditionalize the -W options based on the language of an input file, which is
often painful to do without structural Makefile changes.

Note that there doesn't seem to be any way to squelch this warning, either
(e.g. a -Wno-warning-not-applicable option or similar.)
cc1plus: warning: command-line option ‘-Wmissing-prototypes’ is valid for
C/ObjC but not for C++

[Bug c++/106486] C++ warning for -Wmissing-prototypes is pure nuisance

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106486

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
> which is often painful to do without structural Makefile changes.

Not true. Most makefiles have CFLAGS and CXXFLAGS. And then use a common
OPTFLAGS or something similar. It seems like setting CXXFLAGS directly to
CFLAGS is wrong.

[Bug c++/106486] C++ warning for -Wmissing-prototypes is pure nuisance

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106486

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |egallager at gcc dot gnu.org

--- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to H. Peter Anvin from comment #0)
> Note that there doesn't seem to be any way to squelch this warning, either
> (e.g. a -Wno-warning-not-applicable option or similar.)

I think clang puts it under -Wunknown-warning-option, IIRC...

[Bug c++/106486] C++ warning for -Wmissing-prototypes is pure nuisance

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106486

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-08-01
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  Note that in C++ we effectively have -Werror=missing-prototypes so
maybe we can simply accept -Wmissing-prototypes (but reject
-Wno-missing-prototypes?)

[Bug c++/106486] C++ warning for -Wmissing-prototypes is pure nuisance

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106486

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
You mean accept -Wmissing-prototypes and silently ignore it (because it's
already an error)?

[Bug c++/106486] C++ warning for -Wmissing-prototypes is pure nuisance

[hpa at zytor dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106486

--- Comment #5 from H. Peter Anvin <hpa at zytor dot com> ---
Yes, exactly.