Thank you, for your fast response. > There are some cross-compilation cases > where we can't link, and that's why we only > use AC_TRY_COMPILE.
May you give me some examples of this cases? I had some problems when tries to create toolchain with ulibc-ng and gcc11 for armv5. The problem is that libstdc++ is build with undefined fesetround/fegetround symbols. And compilation of hello-world via this toolchain is fails. This situation may be avoided if libstdc++ checks presence of this symbols at the configuration step. I accepts that it may be a problem of ulibc-ng. But I don’t know for sure. What do you think? вторник, 5 октября 2021 г., 6:12 PM +0300 от Jonathan Wakely <jwak...@redhat.com>: >On Tue, 5 Oct 2021 at 11:32, Petr Mikhalicin wrote: >> >> Autotools tests for libstdc++ check only declaration of required >> symbols, but some symbols may not be defined. >> >> This patch adds trying to link "C99 TR1" tests, not only compile them. >Thanks for the patch. > >N.B. patches for libstdc++ should also be sent to the gcc-patches >list, see https://gcc.gnu.org/contribute.html#patches and >https://gcc.gnu.org/lists.html > >I don't think this patch is OK though. There are some >cross-compilation cases where we can't link, and that's why we only >use AC_TRY_COMPILE. > >> >> Signed-off-by: Petr Mikhalicin < mkh199...@mail.ru > >> --- >> libstdc++-v3/acinclude.m4 | 16 ++++++++-------- >> 1 file changed, 8 insertions(+), 8 deletions(-) >> >> diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 >> index 90ecc4a87a2..8bf8b884a7c 100644 >> --- a/libstdc++-v3/acinclude.m4 >> +++ b/libstdc++-v3/acinclude.m4 >> @@ -1645,7 +1645,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> ac_c99_complex_tr1=no; >> if test x"$ac_has_complex_h" = x"yes"; then >> AC_MSG_CHECKING([for ISO C99 support to TR1 in <complex.h>]) >> - AC_TRY_COMPILE([#include <complex.h>], >> + AC_TRY_LINK( [#include <complex.h>], >> [typedef __complex__ float float_type; float_type tmpf; >> cacosf(tmpf); >> casinf(tmpf); >> @@ -1680,7 +1680,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> # Check for the existence of <ctype.h> functions. >> AC_MSG_CHECKING([for ISO C99 support to TR1 in <ctype.h>]) >> AC_CACHE_VAL(glibcxx_cv_c99_ctype_tr1, [ >> - AC_TRY_COMPILE([#include <ctype.h>], >> + AC_TRY_LINK( [#include <ctype.h>], >> [int ch; >> int ret; >> ret = isblank(ch); >> @@ -1699,7 +1699,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> ac_c99_fenv_tr1=no; >> if test x"$ac_has_fenv_h" = x"yes"; then >> AC_MSG_CHECKING([for ISO C99 support to TR1 in <fenv.h>]) >> - AC_TRY_COMPILE([#include <fenv.h>], >> + AC_TRY_LINK( [#include <fenv.h>], >> [int except, mode; >> fexcept_t* pflag; >> fenv_t* penv; >> @@ -1727,7 +1727,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> # Check for the existence of <stdint.h> types. >> AC_MSG_CHECKING([for ISO C99 support to TR1 in <stdint.h>]) >> AC_CACHE_VAL(glibcxx_cv_c99_stdint_tr1, [ >> - AC_TRY_COMPILE([#define __STDC_LIMIT_MACROS >> + AC_TRY_LINK( [#define __STDC_LIMIT_MACROS >> #define __STDC_CONSTANT_MACROS >> #include <stdint.h>], >> [typedef int8_t my_int8_t; >> @@ -1827,7 +1827,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> # Check for the existence of <math.h> functions. >> AC_MSG_CHECKING([for ISO C99 support to TR1 in <math.h>]) >> AC_CACHE_VAL(glibcxx_cv_c99_math_tr1, [ >> - AC_TRY_COMPILE([#include <math.h>], >> + AC_TRY_LINK( [#include <math.h>], >> [typedef double_t my_double_t; >> typedef float_t my_float_t; >> acosh(0.0); >> @@ -1949,7 +1949,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> darwin*) >> AC_MSG_CHECKING([for ISO C99 rounding functions in <math.h>]) >> AC_CACHE_VAL(glibcxx_cv_c99_math_llround, [ >> - AC_TRY_COMPILE([#include <math.h>], >> + AC_TRY_LINK([#include <math.h>], >> [llrint(0.0); >> llrintf(0.0f); >> llrintl(0.0l); >> @@ -1974,7 +1974,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> ac_c99_inttypes_tr1=no; >> if test x"$glibcxx_cv_c99_stdint_tr1" = x"yes"; then >> AC_MSG_CHECKING([for ISO C99 support to TR1 in <inttypes.h>]) >> - AC_TRY_COMPILE([#include <inttypes.h>], >> + AC_TRY_LINK( [#include <inttypes.h>], >> [intmax_t i, numer, denom, base; >> const char* s; >> char** endptr; >> @@ -1996,7 +1996,7 @@ AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [ >> ac_c99_inttypes_wchar_t_tr1=no; >> if test x"$glibcxx_cv_c99_stdint_tr1" = x"yes"; then >> AC_MSG_CHECKING([for wchar_t ISO C99 support to TR1 in <inttypes.h>]) >> - AC_TRY_COMPILE([#include <inttypes.h>], >> + AC_TRY_LINK( [#include <inttypes.h>], >> [intmax_t base; >> const wchar_t* s; >> wchar_t** endptr; >> -- >> 2.31.1 >> >
