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# ===============================================================================
# https://www.gnu.org/software/autoconf-archive/ax_cxx_have_is_placeholder.html
# ===============================================================================
#
# SYNOPSIS
#
# AX_CXX_HAVE_IS_PLACEHOLDER()
#
# DESCRIPTION
#
# This macro checks if std::is_placeholder, added in C++11, is defined in
# the <functional> header.
#
# If it is, define the ax_cv_cxx_have_is_placeholder environment variable
# to "yes" and define HAVE_CXX_IS_PLACEHOLDER.
#
# LICENSE
#
# Copyright (c) 2014 Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com>
#
# 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 3
AC_DEFUN([AX_CXX_HAVE_IS_PLACEHOLDER],
[AC_CACHE_CHECK(
[for std::is_placeholder in functional],
ax_cv_cxx_have_is_placeholder,
[dnl
AC_LANG_PUSH([C++])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
[
[#include <functional>]
[using std::is_placeholder;]
],
[]
)],
[ax_cv_cxx_have_is_placeholder=yes],
[ax_cv_cxx_have_is_placeholder=no]
)
AC_LANG_POP([C++])])
if test x"$ax_cv_cxx_have_is_placeholder" = "xyes"
then
AC_DEFINE(HAVE_CXX_IS_PLACEHOLDER,
1,
[Define if functional defines the std::is_placeholder class.])
fi
])
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