3 files changed, 46 insertions(+), 3 deletions(-)

M config-daemon.ac
M doc/guix.texi
M m4/guix.m4

@@ 5,9 5,12 @@ AC_MSG_RESULT([$guix_build_daemon])
 
 dnl C++ environment.  This macro must be used unconditionnaly.
 AC_PROG_CXX
+AC_LANG([C++])
 
 if test "x$guix_build_daemon" = "xyes"; then
 
+  GUIX_ASSERT_CXX11
+
   AC_PROG_RANLIB
   AC_CONFIG_HEADER([nix/config.h])
 

@@ 368,9 368,10 @@ Unless @code{--disable-daemon} was passed to @command{configure}, the
 following packages are also needed:
 
 @itemize
-@item @url{http://sqlite.org, SQLite 3}
-@item @url{http://www.bzip.org, libbz2}
-@item @url{http://gcc.gnu.org, GCC's g++}
+@item @url{http://sqlite.org, SQLite 3};
+@item @url{http://www.bzip.org, libbz2};
+@item @url{http://gcc.gnu.org, GCC's g++}, with support for the
+C++11 standard.
 @end itemize
 
 When a working installation of @url{http://nixos.org/nix/, the Nix package

@@ 218,3 218,42 @@ AC_DEFUN([GUIX_CHECK_FILE_NAME_LIMITS], [
     AC_MSG_ERROR([store directory '$storedir' would lead to overly long hash-bang lines])
   fi
 ])
+
+dnl GUIX_CHECK_CXX11
+dnl
+dnl Check whether the C++ compiler can compile a typical C++11 program.
+AC_DEFUN([GUIX_CHECK_CXX11], [
+  AC_REQUIRE([AC_PROG_CXX])
+  AC_CACHE_CHECK([whether $CXX supports C++11],
+    [ac_cv_guix_cxx11_support],
+    [save_CXXFLAGS="$CXXFLAGS"
+     CXXFLAGS="-std=c++11 $CXXFLAGS"
+     AC_COMPILE_IFELSE([
+      AC_LANG_SOURCE([
+	#include <functional>
+
+	std::function<int(int)>
+	return_plus_lambda (int x)
+	{
+	  auto result = [[&]](int y) {
+	    return x + y;
+	  };
+
+	  return result;
+	}
+      ])],
+      [ac_cv_guix_cxx11_support=yes],
+      [ac_cv_guix_cxx11_support=no])
+    CXXFLAGS="$save_CXXFLAGS"
+  ])
+])
+
+dnl GUIX_ASSERT_CXX11
+dnl
+dnl Error out if the C++ compiler cannot compile C++11 code.
+AC_DEFUN([GUIX_ASSERT_CXX11], [
+  GUIX_CHECK_CXX11
+  if test "x$ac_cv_guix_cxx11_support" != "xyes"; then
+    AC_MSG_ERROR([C++ compiler '$CXX' does not support the C++11 standard])
+  fi
+])