# ===========================================================================
#  https://www.gnu.org/software/autoconf-archive/ax_cxx_extern_template.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_CXX_EXTERN_TEMPLATE
#
# DESCRIPTION
#
#   Test whether the C++ compiler supports "extern template".
#
# LICENSE
#
#   Copyright (c) 2008 Patrick Mauritz <oxygene@studentenbude.ath.cx>
#
#   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 8

AU_ALIAS([AC_CXX_EXTERN_TEMPLATE], [AX_CXX_EXTERN_TEMPLATE])
AC_DEFUN([AX_CXX_EXTERN_TEMPLATE],[
AC_CACHE_CHECK(whether the compiler supports extern template,
ax_cv_cxx_extern_template,
[AC_LANG_PUSH([C++])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[template <typename T> void foo(T); extern template void foo<int>(int);]],
 [])],
 [ax_cv_cxx_extern_template=yes], [ax_cv_cxx_extern_template=no])
 AC_LANG_POP([C++])
])
if test "$ax_cv_cxx_extern_template" = yes; then
  AC_DEFINE(HAVE_EXTERN_TEMPLATE,,[define if the compiler supports extern template])
fi
])