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- # ===========================================================================
- # https://www.gnu.org/software/autoconf-archive/ax_cxx_use_numtrait.html
- # ===========================================================================
- #
- # SYNOPSIS
- #
- # AX_CXX_USE_NUMTRAIT
- #
- # DESCRIPTION
- #
- # If the compiler supports numeric traits promotions, define
- # HAVE_USE_NUMTRAIT.
- #
- # LICENSE
- #
- # Copyright (c) 2008 Todd Veldhuizen
- # Copyright (c) 2008 Luc Maisonobe <luc@spaceroots.org>
- #
- # Copying and distribution of this file, with or without modification, are
- # permitted in any medium without royalty provided the copyright notice
- # and this notice are preserved. This file is offered as-is, without any
- # warranty.
-
- #serial 7
-
- AU_ALIAS([AC_CXX_USE_NUMTRAIT], [AX_CXX_USE_NUMTRAIT])
- AC_DEFUN([AX_CXX_USE_NUMTRAIT],
- [AC_CACHE_CHECK(whether the compiler supports numeric traits promotions,
- ax_cv_cxx_use_numtrait,
- [AC_REQUIRE([AX_CXX_TYPENAME])
- AC_LANG_SAVE
- AC_LANG_CPLUSPLUS
- AC_TRY_COMPILE([
- #ifndef HAVE_TYPENAME
- #define typename
- #endif
- template<class T_numtype> class SumType { public : typedef T_numtype T_sumtype; };
- template<> class SumType<char> { public : typedef int T_sumtype; };
- template<class T> class A {};
- template<class T> A<typename SumType<T>::T_sumtype> sum(A<T>)
- { return A<typename SumType<T>::T_sumtype>(); }
- ],[A<float> x; sum(x); return 0;],
- ax_cv_cxx_use_numtrait=yes, ax_cv_cxx_use_numtrait=no)
- AC_LANG_RESTORE
- ])
- if test "$ax_cv_cxx_use_numtrait" = yes; then
- AC_DEFINE(HAVE_USE_NUMTRAIT,,[define if the compiler supports numeric traits promotions])
- fi
- ])
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