[PATCH] libstdc++: Workaround buggy printf on Solaris in to_chars/float128_c++23.cc test [PR107815]

[PATCH] libstdc++: Workaround buggy printf on Solaris in to_chars/float128_c++23.cc test [PR107815]

[Jakub Jelinek]

Hi!

As mentioned in the PR, Solaris apparently can handle right
printf ("%.0Lf\n", 1e+202L * __DBL_MAX__);
which prints 511 chars long number, but can't handle
printf ("%.0Lf\n", 1e+203L * __DBL_MAX__);
nor
printf ("%.0Lf\n", __LDBL_MAX__);
properly, instead of printing 512 chars long number for the former and
4933 chars long number for the second, it handles them as
if user asked for "%.0Le\n" in those cases.

The following patch disables the single problematic value that fails
in the test, and also fixes commented out debugging printouts.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2022-11-24  Jakub Jelinek  <jakub@redhat.com>

	PR libstdc++/107815
	* testsuite/20_util/to_chars/float128_c++23.cc (test): Disable
	__FLT128_MAX__ test on Solaris.  Fix up commented out debugging
	printouts.

--- libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc.jj	2022-11-08 11:19:22.251768167 +0100
+++ libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc	2022-11-23 17:02:22.380051796 +0100
@@ -52,14 +52,17 @@ test(std::chars_format fmt = std::chars_
     std::numbers::inv_sqrt3_v<std::float128_t>,
     std::numbers::egamma_v<std::float128_t>,
     std::numbers::phi_v<std::float128_t>,
+// Solaris has non-conforming printf, see PR98384 and PR107815.
+#if !(defined(__sun__) && defined(__svr4__))
     std::numeric_limits<std::float128_t>::max()
+#endif
   };
   char str1[10000], str2[10000];
   for (auto u : tests)
     {
       auto [ptr1, ec1] = std::to_chars(str1, str1 + sizeof(str1), u, fmt);
       VERIFY( ec1 == std::errc() );
-//    std::cout << i << ' ' << std::string_view (str1, ptr1) << '\n';
+//    std::cout << u << ' ' << std::string_view (str1, ptr1) << '\n';
       if (fmt == std::chars_format::fixed)
 	{
 	  auto [ptr2, ec2] = std::to_chars(str2, str2 + (ptr1 - str1), u, fmt);
@@ -76,7 +79,7 @@ test(std::chars_format fmt = std::chars_
 
       auto [ptr5, ec5] = std::to_chars(str1, str1 + sizeof(str1), u, fmt, 90);
       VERIFY( ec5 == std::errc() );
-//    std::cout << i << ' ' << std::string_view (str1, ptr5) << '\n';
+//    std::cout << u << ' ' << std::string_view (str1, ptr5) << '\n';
       v = 4.0f128;
       auto [ptr6, ec6] = std::from_chars(str1, ptr5, v,
 					 fmt == std::chars_format{}

	Jakub

Re: [PATCH] libstdc++: Workaround buggy printf on Solaris in to_chars/float128_c++23.cc test [PR107815]

[Jonathan Wakely]

On Thu, 24 Nov 2022 at 09:20, Jakub Jelinek wrote:
>
> Hi!
>
> As mentioned in the PR, Solaris apparently can handle right
> printf ("%.0Lf\n", 1e+202L * __DBL_MAX__);
> which prints 511 chars long number, but can't handle
> printf ("%.0Lf\n", 1e+203L * __DBL_MAX__);
> nor
> printf ("%.0Lf\n", __LDBL_MAX__);
> properly, instead of printing 512 chars long number for the former and
> 4933 chars long number for the second, it handles them as
> if user asked for "%.0Le\n" in those cases.
>
> The following patch disables the single problematic value that fails
> in the test, and also fixes commented out debugging printouts.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK, thanks


>
> 2022-11-24  Jakub Jelinek  <jakub@redhat.com>
>
>         PR libstdc++/107815
>         * testsuite/20_util/to_chars/float128_c++23.cc (test): Disable
>         __FLT128_MAX__ test on Solaris.  Fix up commented out debugging
>         printouts.
>
> --- libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc.jj        2022-11-08 11:19:22.251768167 +0100
> +++ libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc   2022-11-23 17:02:22.380051796 +0100
> @@ -52,14 +52,17 @@ test(std::chars_format fmt = std::chars_
>      std::numbers::inv_sqrt3_v<std::float128_t>,
>      std::numbers::egamma_v<std::float128_t>,
>      std::numbers::phi_v<std::float128_t>,
> +// Solaris has non-conforming printf, see PR98384 and PR107815.
> +#if !(defined(__sun__) && defined(__svr4__))
>      std::numeric_limits<std::float128_t>::max()
> +#endif
>    };
>    char str1[10000], str2[10000];
>    for (auto u : tests)
>      {
>        auto [ptr1, ec1] = std::to_chars(str1, str1 + sizeof(str1), u, fmt);
>        VERIFY( ec1 == std::errc() );
> -//    std::cout << i << ' ' << std::string_view (str1, ptr1) << '\n';
> +//    std::cout << u << ' ' << std::string_view (str1, ptr1) << '\n';
>        if (fmt == std::chars_format::fixed)
>         {
>           auto [ptr2, ec2] = std::to_chars(str2, str2 + (ptr1 - str1), u, fmt);
> @@ -76,7 +79,7 @@ test(std::chars_format fmt = std::chars_
>
>        auto [ptr5, ec5] = std::to_chars(str1, str1 + sizeof(str1), u, fmt, 90);
>        VERIFY( ec5 == std::errc() );
> -//    std::cout << i << ' ' << std::string_view (str1, ptr5) << '\n';
> +//    std::cout << u << ' ' << std::string_view (str1, ptr5) << '\n';
>        v = 4.0f128;
>        auto [ptr6, ec6] = std::from_chars(str1, ptr5, v,
>                                          fmt == std::chars_format{}
>
>         Jakub
>