Question

Hey guys,
This could be a noob question, but I really can’t find any useful solution through Google.
I’m testing a hello world with boost.asio, the program is quite simple:

#include <iostream>
#include <boost/asio.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
int main()
{
    boost::asio::io_service io;
    boost::asio::deadline_timer t(io, boost::posix_time::seconds(5));
    t.wait();
    std::cout << "Hello, world!\n";
    return 0;
}

I passed the compilation and run well on my Intel Pentium PC (Ubuntu 10.10, gcc 4.4.5, Boost 1.46.0). The command line I used was

g++ -o a a.cpp -I /Boost-Include-Path/ -L /Boost-lib-Path/ -lboost_system

But when I compile the same code on another machine(which is a big one, I’ll explain it later), it can’t pass the compilation and gives such errors:

---

/tmp/ccOZxZBX.o: In function boost::asio::detail::gcc_sync_fenced_block::gcc_sync_fenced_block()': a.cpp:(.text._ZN5boost4asio6detail21gcc_sync_fenced_blockC1Ev[boost::asio::detail::gcc_sync_fenced_block::gcc_sync_fenced_block()]+0x4c): undefined reference to__sync_lock_test_and_set_4′ /tmp/ccOZxZBX.o: In function boost::detail::atomic_count::operator++()': a.cpp:(.text._ZN5boost6detail12atomic_countppEv[boost::detail::atomic_count::operator++()]+0x30): undefined reference to__sync_add_and_fetch_8′ /tmp/ccOZxZBX.o: In function boost::detail::atomic_count::operator--()': a.cpp:(.text._ZN5boost6detail12atomic_countmmEv[boost::detail::atomic_count::operator--()]+0x30): undefined reference to__sync_add_and_fetch_8′ /tmp/ccOZxZBX.o: In function boost::detail::atomic_count::operator long() const': a.cpp:(.text._ZNK5boost6detail12atomic_countcvlEv[boost::detail::atomic_count::operator long() const]+0x30): undefined reference to__sync_fetch_and_add_8′

---

The machine I used was a SiCortex SC5832,which use MIPS64 instruction set processors, OS is changed CentoOS. Gcc 4.2.3, Boost1.46.0. Is it possible that there are problems about the compatibility of the MIPS? I added -mips64 option, but it still give the same errors.
I know this environment could not be very usual, but I think some people who are using similar big machines may face the same problem.

Any help would be appreciated. By the way, I don’t have sudo permission.

Thanks,
Tony

Answer 1

This function is a GCC built-in function, and it was introduced around GCC 4.2 (iirc) see documentation.

According to the documentation it’s not available on all target processors.

If you look at boost/smart_ptr/detail/atomic_count.hpp it looks like it would fall into the #elif defined(BOOST_SP_HAS_SYNC) block. i.e. boost/smart_ptr/detail/atomic_count_sync.hpp.

Support for this is determined in boost/smart_ptr/detail/sp_has_sync.hpp. This header essentially assumes that GCC supports this on all platforms except for a few exceptions. You might want to insert MIPS as another exception here and submit a patch to boost.

You’ll also see that one workaround is to define BOOST_AC_USE_PTHREADS. This will use a mutex around the atomic count, which probably is significantly less efficient, but at least it will work until you can figure out what atomic operations are supported on MIPS64.