Re: [PATCH v1] make: ensure a consistent C++ standard use

Re: [PATCH v1] make: ensure a consistent C++ standard use

[Dodji Seketeli]

Hello,

Matthias Maennich <maennich@google.com> a écrit:

> On older compilers (such as g++ 4.8), the default C++ standard is set to
> gnu++98. When compiling libabigail with --enable-cxx11=yes, src/ and
> tests/ where compiled with the correct flag, while tools/ was compiled
> without specifying a standard. With a compiler falling back to gnu++98
> that leads to unresolved references when linking the tools against the
> libabigail library. Fix that by consistently using the std= flag across
> the code base.
>
> 	* configure.ac: add -std=c++11 flag to CXXFLAGS when compiling
> 	for C++11
> 	* src/Makefile.am: drop now obsolete setting of the -std flag
> 	* tests/Makefile.am: likewise

This looks good to me, so I have pushed it to master.

The only nit I have picked is that I merged the hunk below

    > +if test x$ENABLE_CXX11 = xyes; then
    > +    CXXFLAGS="$CXXFLAGS -std=c++11"
    > +fi

with the spot in the configure.ac file where we were already handling
the C++11 enabling.  So the change to configure.ac became:

    diff --git a/configure.ac b/configure.ac
    index afcc1db..44e951f 100644
    --- a/configure.ac
    +++ b/configure.ac
    @@ -545,6 +545,7 @@ AC_SUBST(DEPS_CPPFLAGS)

     dnl Handle conditional use of a C++11 compiler
     if test x$ENABLE_CXX11 = xyes; then
    +   CXXFLAGS="$CXXFLAGS -std=c++11"
        AC_DEFINE([WITH_CXX11], 1, [Defined to 1 if a C++11 compiler is used])
     fi
 
Thanks a lot for taking the time to prepare this patch!

Cheers,

-- 
		Dodji

[PATCH v1] make: ensure a consistent C++ standard use

[Matthias Maennich via libabigail]

On older compilers (such as g++ 4.8), the default C++ standard is set to
gnu++98. When compiling libabigail with --enable-cxx11=yes, src/ and
tests/ where compiled with the correct flag, while tools/ was compiled
without specifying a standard. With a compiler falling back to gnu++98
that leads to unresolved references when linking the tools against the
libabigail library. Fix that by consistently using the std= flag across
the code base.

	* configure.ac: add -std=c++11 flag to CXXFLAGS when compiling
	for C++11
	* src/Makefile.am: drop now obsolete setting of the -std flag
	* tests/Makefile.am: likewise

Reported-by: Chun-Hung Wu <Chun-hung.Wu@mediatek.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
---
 configure.ac      | 4 ++++
 src/Makefile.am   | 1 -
 tests/Makefile.am | 1 -
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index afcc1db065e9..54ab695ae1e4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -607,6 +607,10 @@ if test x$ENABLE_UBSAN = xyes; then
     CXXFLAGS="$CXXFLAGS -fsanitize=undefined"
 fi
 
+if test x$ENABLE_CXX11 = xyes; then
+    CXXFLAGS="$CXXFLAGS -std=c++11"
+fi
+
 dnl Check if several decls and constant are defined in dependant
 dnl libraries
 HAS_EM_AARCH64=no
diff --git a/src/Makefile.am b/src/Makefile.am
index 7c02d538c50d..1d0e2dcecdee 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -7,7 +7,6 @@ if ENABLE_CXX11
 CXX11_SOURCES = abg-viz-common.cc			\
 		abg-viz-dot.cc				\
 		abg-viz-svg.cc
-AM_CXXFLAGS += "-std=c++11"
 else
 CXX11_SOURCES =
 endif
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 2104300aed22..14e83608b0e5 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -13,7 +13,6 @@ AM_CXXFLAGS = $(VISIBILITY_FLAGS)
 CXX11_TESTS =
 if ENABLE_CXX11
 CXX11_TESTS += runtestsvg
-AM_CXXFLAGS += "-std=c++11"
 endif
 
 FEDABIPKGDIFF_TEST =
-- 
2.22.0.657.g960e92d24f-goog