On Mon, Jan 21, 2013 at 10:38:15PM -0800, Paul Eggert wrote:
> On 01/21/2013 12:36 PM, Roger Leigh wrote:
> > For C stuff like
> > const/restrict/volatile/inline, it's possible to achieve this
> > fairly simply, and autoconf does a very good job here.
> >
> > However, if you look at the C++11 features like declspec,
> > automatic type inference, array initialisers, delegate
> > constructors, range-based for loops, lambdas, etc. these
> > features can not be substituted for.
>
> On 01/21/2013 04:01 PM, Miles Bader wrote:
> > If you need C++11 features and don't have any compatibility fallbacks,
> > isn't following the autoconf language test in configure.ac by
> > "if not c++11 then AC_ERROR([BARF! Need a C++11 compiler!])" good
> > enough?
That would probably satisfy my own particular use case sufficiently.
Please find attached a reworked and simplified patch. This patch
adds no user-visible macros, and removes the TR1 checks which can
be done simply enough by the user. This means it will check for
only C++11 and C++98. We have the specific ac_cv_prog_cxx_cxx11
and ac_cv_prog_cxx_cxx98 which are both set to no if unavailable,
exactly like for C, and these can be checked to see if the
compiler satisfies your requirements.
Hope that's all OK with you.
Regards,
Roger
--
.''`. Roger Leigh
: :' : Debian GNU/Linux http://people.debian.org/~rleigh/
`. `' schroot and sbuild http://alioth.debian.org/projects/buildd-tools
`- GPG Public Key F33D 281D 470A B443 6756 147C 07B3 C8BC 4083 E800
>From 0000f0aeac4c1b883dd01fd978a629a97220ca88 Mon Sep 17 00:00:00 2001
From: Roger Leigh <rle...@debian.org>
Date: Sun, 20 Jan 2013 18:50:49 +0000
Subject: [PATCH] AC_PROG_CXX: Add checks for C++11, C++98TR1 and C++98
These checks are the C++ equivalent of the existing C
standards checks.
---
doc/autoconf.texi | 30 ++++-
lib/autoconf/c.m4 | 336 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 365 insertions(+), 1 deletion(-)
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index bb83443..2d6d866 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -7642,6 +7642,35 @@ like this:
AC_PROG_CXX([gcc cl KCC CC cxx cc++ xlC aCC c++ g++])
@end example
+If necessary, add an option to output variable @code{CXX} to enable
+support for ISO Standard C++ features with extensions. Prefer the
+newest C++ standard that is supported. Currently the newest standard is
+ISO C++11, with ISO C++98 being the previous standard. After calling
+this macro you can check whether the C++ compiler has been set to accept
+Standard C++; if not, the shell variable @code{ac_cv_prog_cxx_stdcxx} is
+set to @samp{no}. If the C++ compiler will not accept C++11, the shell
+variable @code{ac_cv_prog_cxx_cxx11} is set to @samp{no}, and if it will
+not accept C++98, the shell variable @code{ac_cv_prog_cxx_cxx98} is set
+to @samp{no}.
+
+When attempting to add compiler options, prefer extended functionality
+to strict conformance: the goal is to enable whatever standard features
+that are available, not to check for full conformance to the standard or
+to prohibit incompatible extensions. Test for C++11 support by checking
+for the language features @code{auto}, @code{constexpr},
+@code{decltype}, @code{default}ed and @code{delete}ed constructors,
+delegate constructors, @code{final}, initializer lists, lambda
+functions, @code{nullptr}, @code{override}, range-based for loops,
+template brackets without spaces and unicode literals, and library
+features @code{std::array}, @code{std::shared_ptr},
+@code{std::weak_ptr}, @code{std::regex} and @code{std::tuple}. Test for
+C++98 support using basic features of the @code{std} namespace including
+@code{std::string}, containers (@code{std::list}, @code{std::map},
+@code{std::set}, @code{std::vector}), streams (fstreams, iostreams,
+stringstreams, iomanip), @code{std::pair}, exceptions (@code{try},
+@code{catch} and @code{std::runtime_error}) and algorithms. Tests for
+more recent standards include all the tests for older standards.
+
If using the GNU C++ compiler, set shell variable @code{GXX} to
@samp{yes}. If output variable @code{CXXFLAGS} was not already set, set
it to @option{-g -O2} for the GNU C++ compiler (@option{-O2} on
@@ -7649,7 +7678,6 @@ systems where G++ does not accept @option{-g}), or @option{-g} for other
compilers. If your package does not like this default, then it is
acceptable to insert the line @samp{: $@{CXXFLAGS=""@}} after @code{AC_INIT}
and before @code{AC_PROG_CXX} to select an empty default instead.
-
@end defmac
@defmac AC_PROG_CXXCPP
diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
index affd765..6fe00fb 100644
--- a/lib/autoconf/c.m4
+++ b/lib/autoconf/c.m4
@@ -749,6 +749,13 @@ else
GXX=
fi
_AC_PROG_CXX_G
+_AC_PROG_CXX_CXX11([ac_prog_cxx_stdcxx=cxx11
+ ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx11
+ ac_cv_prog_cxx_cxx98=$ac_cv_prog_cxx_cxx11],
+ [_AC_PROG_CXX_CXX98([ac_prog_cxx_stdcxx=cxx98
+ ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx98],
+ [ac_prog_cxx_stdcxx=no
+ ac_cv_prog_cxx_stdcxx=no])])
AC_LANG_POP(C++)dnl
])# AC_PROG_CXX
@@ -2158,3 +2165,332 @@ AC_DEFUN([AC_OPENMP],
fi
AC_SUBST([OPENMP_]_AC_LANG_PREFIX[FLAGS])
])
+
+# _AC_CXX_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
+# ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
+# ----------------------------------------------------------------
+# Check whether the C++ compiler accepts features of STANDARD (e.g
+# `cxx98', `cxx11') by trying to compile a program of TEST-PROLOGUE
+# and TEST-BODY. If this fails, try again with each compiler option
+# in the space-separated OPTION-LIST; if one helps, append it to CXX.
+# If eventually successful, run ACTION-IF-AVAILABLE, else
+# ACTION-IF-UNAVAILABLE.
+AC_DEFUN([_AC_CXX_STD_TRY],
+[AC_MSG_CHECKING([for $CXX option to enable ]m4_translit(m4_translit($1, [x], [+]), [a-z], [A-Z])[ features])
+AC_LANG_PUSH(C++)dnl
+AC_CACHE_VAL(ac_cv_prog_cxx_$1,
+[ac_cv_prog_cxx_$1=no
+ac_save_CXX=$CXX
+AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
+for ac_arg in '' $4
+do
+ CXX="$ac_save_CXX $ac_arg"
+ _AC_COMPILE_IFELSE([], [ac_cv_prog_cxx_$1=$ac_arg])
+ test "x$ac_cv_prog_cxx_$1" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CXX=$ac_save_CXX
+])# AC_CACHE_VAL
+ac_prog_cxx_stdcxx_options=
+case "x$ac_cv_prog_cxx_$1" in
+ x)
+ AC_MSG_RESULT([none needed]) ;;
+ xno)
+ AC_MSG_RESULT([unsupported]) ;;
+ *)
+ ac_prog_cxx_stdcxx_options=" $ac_cv_prog_cxx_$1"
+ CXX=$CXX$ac_prog_cxx_stdcxx_options
+ AC_MSG_RESULT([$ac_cv_prog_cxx_$1]) ;;
+esac
+AC_LANG_POP(C++)dnl
+AS_IF([test "x$ac_cv_prog_cxx_$1" != xno], [$5], [$6])
+])# _AC_CXX_STD_TRY
+
+# _AC_CXX_CXX98_TEST_HEADER
+# -------------------------
+# A C++ header suitable for testing for CXX98.
+AC_DEFUN([_AC_CXX_CXX98_TEST_HEADER],
+[[
+#include <algorithm>
+#include <cstdlib>
+#include <fstream>
+#include <iomanip>
+#include <iostream>
+#include <list>
+#include <map>
+#include <set>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace test {
+ typedef std::vector<std::string> string_vec;
+ typedef std::pair<int,bool> map_value;
+ typedef std::map<std::string,map_value> map_type;
+ typedef std::set<int> set_type;
+
+ template<typename T>
+ class printer {
+ public:
+ printer(std::ostringstream& os): os(os) {}
+ void operator() (T elem) { os << elem << std::endl; }
+ private:
+ std::ostringstream& os;
+ };
+}
+]])# _AC_CXX_CXX98_TEST_HEADER
+
+# _AC_CXX_CXX98_TEST_BODY
+# -----------------------
+# A C++ body suitable for testing for CXX98, assuming the corresponding header.
+AC_DEFUN([_AC_CXX_CXX98_TEST_BODY],
+[[
+
+try {
+ // Basic string.
+ std::string teststr("ASCII text");
+ teststr += " string";
+
+ // Simple vector.
+ test::string_vec testvec;
+ testvec.push_back(teststr);
+ testvec.push_back("foo");
+ testvec.push_back("bar");
+ if (testvec.size() != 3) {
+ throw std::runtime_error("Vector size is not 1");
+ }
+
+ // Dump vector into stringstream and obtain string.
+ std::ostringstream os;
+ for (test::string_vec::const_iterator i = testvec.begin();
+ i != testvec.end(); ++i) {
+ if (i + 1 != testvec.end()) {
+ os << teststr << '\n';
+ }
+ }
+ // Check algorithms work.
+ std::for_each(testvec.begin(), testvec.end(), test::printer<std::string>(os));
+ std::string os_out = os.str();
+
+ // Test pair and map.
+ test::map_type testmap;
+ testmap.insert(std::make_pair(std::string("key"),
+ std::make_pair(53,false)));
+
+ // Test set.
+ int values[] = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
+ test::set_type testset(values, values + sizeof(values)/sizeof(values[0]));
+ std::list<int> testlist(testset.begin(), testset.end());
+ std::copy(testset.begin(), testset.end(), std::back_inserter(testlist));
+} catch (const std::exception& e) {
+ std::cerr << "Caught exception: " << e.what() << std::endl;
+
+ // Test fstream
+ std::ofstream of("test.txt");
+ of << "Test ASCII text\n" << std::flush;
+ of << "N= " << std::hex << std::setw(8) << std::left << 534 << std::endl;
+ of.close();
+}
+std::exit(0);
+]])
+
+# _AC_CXX_CXX11_TEST_HEADER
+# -------------------------
+# A C++ header suitable for testing for CXX11.
+AC_DEFUN([_AC_CXX_CXX11_TEST_HEADER],
+[[
+#include <deque>
+#include <functional>
+#include <memory>
+#include <tuple>
+#include <array>
+#include <regex>
+#include <iostream>
+
+namespace cxx11test
+{
+ typedef std::shared_ptr<std::string> sptr;
+ typedef std::weak_ptr<std::string> wptr;
+
+ typedef std::tuple<std::string,int,double> tp;
+ typedef std::array<int, 20> int_array;
+
+ constexpr int get_val() { return 20; }
+
+ struct testinit
+ {
+ int i;
+ double d;
+ };
+
+ class delegate {
+ public:
+ delegate(int n) : n(n) {}
+ delegate(): delegate(2354) {}
+
+ virtual int getval() { return this->n; };
+ protected:
+ int n;
+ };
+
+ class overridden : public delegate {
+ public:
+ overridden(int n): delegate(n) {}
+ virtual int getval() override final { return this->n * 2; }
+ };
+
+ class nocopy {
+ public:
+ nocopy(int i): i(i) {}
+ nocopy() = default;
+ nocopy(const nocopy&) = delete;
+ nocopy & operator=(const nocopy&) = delete;
+ private:
+ int i;
+ };
+}
+]])# _AC_CXX_CXX11_TEST_HEADER
+
+# _AC_CXX_CXX11_TEST_BODY
+# -----------------------
+# A C++ body suitable for testing for CXX11, assuming the corresponding header.
+AC_DEFUN([_AC_CXX_CXX11_TEST_BODY],
+[[
+{
+ // Test auto and decltype
+ std::deque<int> d;
+ d.push_front(43);
+ d.push_front(484);
+ d.push_front(3);
+ d.push_front(844);
+ int total = 0;
+ for (auto i = d.begin(); i != d.end(); ++i) { total += *i; }
+
+ auto a1 = 6538;
+ auto a2 = 48573953.4;
+ auto a3 = "String literal";
+
+ decltype(a2) a4 = 34895.034;
+}
+{
+ // Test constexpr
+ short sa[cxx11test::get_val()] = { 0 };
+}
+{
+ // Test initialiser lists
+ cxx11test::testinit il = { 4323, 435234.23544 };
+}
+{
+ // Test range-based for and lambda
+ cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
+ for (int &x : array) { x += 23; }
+ std::for_each(array.begin(), array.end(), [](int v1){ std::cout << v1; });
+}
+{
+ using cxx11test::sptr;
+ using cxx11test::wptr;
+
+ sptr sp(new std::string("ASCII string"));
+ wptr wp(sp);
+ sptr sp2(wp);
+}
+{
+ cxx11test::tp tuple("test", 54, 45.53434);
+ double d = std::get<2>(tuple);
+ std::string s;
+ int i;
+ std::tie(s,i,d) = tuple;
+}
+{
+ static std::regex filename_regex("^_?([a-z0-9_.]+-)+[a-z0-9]+$");
+ std::string testmatch("Test if this string matches");
+ bool match = std::regex_search(testmatch, filename_regex);
+}
+{
+ cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
+ cxx11test::int_array::size_type size = array.size();
+}
+{
+ // Test constructor delegation
+ cxx11test::delegate d1;
+ cxx11test::delegate d2();
+ cxx11test::delegate d3(45);
+}
+{
+ // Test override and final
+ cxx11test::overridden o1(55464);
+}
+{
+ // Test nullptr
+ char *c = nullptr;
+}
+{
+ // Test template brackets
+ std::vector<std::pair<int,char*>> v1;
+}
+{
+ // Unicode literals
+ char *utf8 = u8"UTF-8 string \u2500";
+ char16_t *utf16 = u"UTF-8 string \u2500";
+ char32_t *utf32 = U"UTF-32 string \u2500";
+}
+]])
+
+# _AC_PROG_CXX_CXX98 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
+# -------------------------------------------------------------------
+
+# If the C++ compiler is not in ISO C++98 mode by default, try to add
+# an option to output variable CXX to make it so. This macro tries
+# various options that select ISO C++98 on some system or another. It
+# considers the compiler to be in ISO C++98 mode if it handles basic
+# features of the std namespace including: string, containers (list,
+# map, set, vector), streams (fstreams, iostreams, stringstreams,
+# iomanip), pair, exceptions and algorithms.
+
+
+AC_DEFUN([_AC_PROG_CXX_CXX98],
+[_AC_CXX_STD_TRY([cxx98],
+[_AC_CXX_CXX98_TEST_HEADER],
+[_AC_CXX_CXX98_TEST_BODY],
+dnl Try
+dnl GCC -std=gnu++98 (unused restrictive mode: -std=c++98)
+dnl IBM XL C -qlanglvl=extended
+dnl HP aC++ -AA
+dnl Intel ICC -std=gnu++98
+dnl Solaris N/A (default)
+dnl Tru64 N/A (default, but -std gnu could be used)
+dnl with extended modes being tried first.
+[[-std=gnu++98 -std=c++98 -qlanglvl=extended -AA]], [$1], [$2])[]dnl
+])# _AC_PROG_CXX_CXX98
+
+# _AC_PROG_CXX_CXX11 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
+# -------------------------------------------------------------------
+# If the C++ compiler is not in ISO CXX11 mode by default, try to add
+# an option to output variable CXX to make it so. This macro tries
+# various options that select ISO C++11 on some system or another. It
+# considers the compiler to be in ISO C++11 mode if it handles all the
+# tests from the C++98 checks, plus the following: Language features
+# (auto, constexpr, decltype, default/deleted constructors, delegate
+# constructors, final, initialiser lists, lambda functions, nullptr,
+# override, range-based for loops, template brackets without spaces,
+# unicode literals) and library features (array, memory (shared_ptr,
+# weak_ptr), regex and tuple types).
+AC_DEFUN([_AC_PROG_CXX_CXX11],
+[_AC_CXX_STD_TRY([cxx11],
+[_AC_CXX_CXX11_TEST_HEADER
+_AC_CXX_CXX98_TEST_HEADER],
+[_AC_CXX_CXX11_TEST_BODY
+_AC_CXX_CXX98_TEST_BODY],
+dnl Try
+dnl GCC -std=gnu++11 (unused restrictive mode: -std=c++11) [and 0x variants]
+dnl IBM XL C -qlanglvl=extended0x
+dnl (pre-V12.1; unused restrictive mode: -qlanglvl=stdcxx11)
+dnl HP aC++ -AA
+dnl Intel ICC -std=c++11 -std=c++0x
+dnl Solaris N/A (no support)
+dnl Tru64 N/A (no support)
+dnl with extended modes being tried first.
+[[-std=gnu++11 -std=c++11 -std=gnu++0x -std=c++0x -qlanglvl=extended0x -AA]], [$1], [$2])[]dnl
+])# _AC_PROG_CXX_CXX11
--
1.7.10.4
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