Getting GCC in C++11 mode to work on FreeBSD

Question

How do I get a working GCC-based C++11 setup on FreeBSD 10? It seems that the standard library that comes with recent GCC versions on FreeBSD is broken. I've installed the port gcc49 and then try to compile this:

#include <string>

int main()
{
  auto str = std::to_string(42);
  str = std::to_string(42ull);
  str = std::to_string(4.2);
  str.clear();
  return 0;
}

This gives me an error:

g++49 -v -std=c++11 foo.cc
Using built-in specs.
COLLECT_GCC=g++49
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc49/gcc/x86_64-portbld-freebsd10.0/4.9.2/lto-wrapper
Target: x86_64-portbld-freebsd10.0
Configured with: ./../gcc-4.9-20141022/configure --disable-nls --enable-gnu-indirect-function --libdir=/usr/local/lib/gcc49 --libexecdir=/usr/local/libexec/gcc49 --program-suffix=49 --with-as=/usr/local/bin/as --with-gmp=/usr/local --with-gxx-include-dir=/usr/local/lib/gc
c49/include/c++/ --with-ld=/usr/local/bin/ld --with-pkgversion='FreeBSD Ports Collection' --with-system-zlib --with-ecj-jar=/usr/local/share/java/ecj-4.5.jar --enable-languages=c,c++,objc,fortran,java --prefix=/usr/local --mandir=/usr/local/man --infodir=/usr/local/info/gcc49 --build=x86_64-portbld-freebsd10.0
Thread model: posix
gcc version 4.9.2 20141022 (prerelease) (FreeBSD Ports Collection) 
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
 /usr/local/libexec/gcc49/gcc/x86_64-portbld-freebsd10.0/4.9.2/cc1plus -quiet -v foo.cc -quiet -dumpbase foo.cc -mtune=generic -march=x86-64 -auxbase foo -std=c++11 -version -o /tmp//ccbNFhtI.s
GNU C++ (FreeBSD Ports Collection) version 4.9.2 20141022 (prerelease) (x86_64-portbld-freebsd10.0)
        compiled by GNU C version 4.9.2 20141022 (prerelease), GMP version 5.1.3, MPFR version 3.1.2, MPC version 1.0.2
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/lib/gcc49/gcc/x86_64-portbld-freebsd10.0/4.9.2/../../../../../x86_64-portbld-freebsd10.0/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/lib/gcc49/include/c++/
 /usr/local/lib/gcc49/include/c++//x86_64-portbld-freebsd10.0
 /usr/local/lib/gcc49/include/c++//backward
 /usr/local/lib/gcc49/gcc/x86_64-portbld-freebsd10.0/4.9.2/include
 /usr/local/include
 /usr/local/lib/gcc49/gcc/x86_64-portbld-freebsd10.0/4.9.2/include-fixed
 /usr/include
End of search list.
GNU C++ (FreeBSD Ports Collection) version 4.9.2 20141022 (prerelease) (x86_64-portbld-freebsd10.0)
        compiled by GNU C version 4.9.2 20141022 (prerelease), GMP version 5.1.3, MPFR version 3.1.2, MPC version 1.0.2
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 8405316ee381c37148f55a17e42da47a
foo.cc: In function 'int main()':
foo.cc:5:14: error: 'to_string' is not a member of 'std'
   auto str = std::to_string(42);
              ^
foo.cc:6:9: error: 'to_string' is not a member of 'std'
   str = std::to_string(42ull);
         ^
foo.cc:7:9: error: 'to_string' is not a member of 'std'
   str = std::to_string(4.2);
         ^

The default include search path is /usr/local/lib/gcc49/include/c++/, which does contain the string header. Makes sense, because the gcc49 port ships with a corresponding libstc++. But it seems broken, per the above error.

Is this a known problem? Has anyone gotten a working setup of a GCC-based toolchain for C++11 on FreeBSD?

(Note: I'm aware that Clang is the default compiler on FreeBSD 10. But in this case I'm specifically looking to support a GCC-based toolchain.)

Answer 1

Turns out that adding the following flags to g++ will make it work:

-D_GLIBCXX_USE_C99 -D_GLIBCXX_USE_C99_MATH -D_GLIBCXX_USE_C99_MATH_TR1