Re: [Tinycc-devel] Add max_align_t to stddef.h and C11

[uso ewin]

On Tue, Jan 8, 2019 at 5:06 PM Christian Jullien <address@hidden> wrote:
>
> If no one protests, I can push this patch:
> address@hidden:~/new-tcc $ git diff
> diff --git a/libtcc.c b/libtcc.c
> index df7adab..eb55d8a 100644
> --- a/libtcc.c
> +++ b/libtcc.c
> @@ -1790,8 +1790,15 @@ reparse:
>              s->static_link = 1;
>              break;
>          case TCC_OPTION_std:
> -           /* silently ignore, a current purpose:
> -              allow to use a tcc as a reference compiler for "make test" */
> +            if (*optarg == '=') {
> +                ++optarg;
> +                if (strcmp(optarg, "c11") == 0) {
> +                   tcc_undefine_symbol(s, "__STDC_VERSION__");
> +                   tcc_define_symbol(s, "__STDC_VERSION__", "201112L");
> +                }
> +            }
> +             /* silently ignore other values, a current purpose:
> +                allow to use a tcc as a reference compiler for "make test"
> */
>              break;
>          case TCC_OPTION_shared:
>              x = TCC_OUTPUT_DLL;
> diff --git a/tcc.c b/tcc.c
> index f780389..2d4e1ea 100644
> --- a/tcc.c
> +++ b/tcc.c
> @@ -33,6 +33,8 @@ static const char help[] =
>      "  -o outfile  set output filename\n"
>      "  -run        run compiled source\n"
>      "  -fflag      set or reset (with 'no-' prefix) 'flag' (see tcc -hh)\n"
> +    "  -std=c99    Conform to the ISO 1999 C standard (default).\n"
> +    "  -std=c11    Conform to the ISO 2011 C standard.\n"
>      "  -Wwarning   set or reset (with 'no-' prefix) 'warning' (see tcc
> -hh)\n"
>      "  -w          disable all warnings\n"
>      "  -v -vv      show version, show search paths or loaded files\n"
>
> It allows to start to play with -std=c11 new option. It correctly handles
> c11 and ignore all other values to be compatible with gcc.
>
> address@hidden:~/new-tcc $ cat foo.c
> #include <stdio.h>
>
> int
> main() {
>         printf("__STDC_VERSION__ == %d\n", __STDC_VERSION__);
> }
> address@hidden:~/new-tcc $ ./tcc foo.c -o foo && ./foo
> __STDC_VERSION__ == 199901
> address@hidden:~/new-tcc $ ./tcc -std=c11 foo.c -o foo && ./foo
> __STDC_VERSION__ == 201102
> address@hidden:~/new-tcc $ ./tcc -std=c42 foo.c -o foo && ./foo
> __STDC_VERSION__ == 199901
>
>
>
> -----Original Message-----
> From: Tinycc-devel [mailto:address@hidden
> On Behalf Of uso ewin
> Sent: mardi 8 janvier 2019 15:31
> To: address@hidden
> Subject: Re: [Tinycc-devel] Add max_align_t to stddef.h and C11
>
> On Tue, Jan 8, 2019 at 2:35 PM Christian Jullien <address@hidden> wrote:
> >
> > IMHO,
> >
> > The right solution is to start to implement C11 features and surround them
> > with right #if _STDC_VERSION >= xxx.
> > This is how gcc/Linux handle differences between C/C++/POSIX/...
> >
> > Even gcc is not totally fair when it claims it supports a given version.
> >
> > I spent several hours to figure out why my -std=c++11 regexp always
> returned
> > false with gcc 4.8.2 until I discovered that <regexp> and all API was
> > present ... BUT NOT IMPLEMENTED and all calls where returning error!!!
> >
> > I personally vote in favor of -std=c11 new option which supports ... only
> > what is actually implemented (without complex for instance).
> >
> > What other maintainers think about by opinion?
> >
>
> I'm not a maintainer, but am totally in favor to add a support for -std=C11
> and  maybe latter for -std=C99.
>
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Maybe add a global variable
int c_version = 99;
and set it to 11 if std=c11 is use
so we can directly use this variable to "disable" C11 feature when C11
isn't set.
also, (but not completely related to the subject)
it could be interesting to add support for std=gnu11/99 (but not in
the same commit as this could bring bugs)
so we can define _GNUC_ which would make gcc attribute easier to use