Re: [PATCH 1/5] posix: Sync regex code with gnulib

[Vaseeharan Vinayagamoorthy via Libc-alpha <libc-alpha@sourceware.org>]

Thanks for the fix, Adhemerval Zanella.
I assume you would fix this in other files too, for example I think a similar patch is needed for posix/fnmatch.c.

fnmatch.c:67:26: error: "__clang_major__" is not defined [-Werror=undef]
 # if (__GNUC__ >= 7) || (__clang_major__ >= 10)
                          ^~~~~~~~~~~~~~~



On 20/01/2021, 11:27, "Adhemerval Zanella" <adhemerval.zanella@linaro.org> wrote:



    On 19/01/2021 23:55, Paul Eggert wrote:
    > On 1/19/21 7:43 AM, Bruno Haible wrote:
    >> Adhemerval Zanella wrote:
    >>> -# if (__GNUC__ >= 7) || (__clang_major__ >= 10)
    >>> +# if (__GNUC__ >= 7) || (defined __clang_major__ &&__clang_major__ >= 10)
    >> I would write it as:
    >>
    >> +# if (__GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
    > 
    > This line should be used only if _LIBC is defined, so we can simplify it to just "#if __GNUC__ >= 7" and thus not worry about Clang.
    > 
    > I see that Gnulib wasn't consistent about this, so I installed the attached patch to Gnulib to fix the issue here and elsewhere. The idea is that the Gnulib regex_internal.h can be copied back to glibc, and that the other uses in Gnulib should be similar.

    Thanks, I will check with a bootstrap build and sync regex_internal.h
    with glibc.

    > 
    > On 1/19/21 6:43 AM, Adhemerval Zanella wrote:
    > 
    >> Paul, this seemed to a common pattern scatter on multiple file in gnulib.
    >> Wouldn't be better to consolidate it on cdefs.h?
    > 
    > We could append something like the following to cdefs.h, and switch to __attribute_fallthrough__ for modules shared between the two systems. Is that something you'd like to pursue? (We should also sync Gnulib cdefs.h back to glibc of course.)
    > 
    > #if defined __STDC_VERSION__ && 201710L < __STDC_VERSION__
    > # define __attribute_fallthrough__ [[__fallthrough__]]
    > #elif __GNUC_PREREQ (7, 0) || __glibc_has_attribute (__fallthrough__)
    > # define __attribute_fallthrough__ __attribute__ ((__fallthrough__))
    > #else
    > # define __attribute_fallthrough__ ((void) 0)
    > #endif

    Yes, for 2.34 I will send some patches to sync the remaining gnulib
    files and document from our part the shared files.