Question

I have a very simple example program that I am trying to compile, but I’m getting linking errors.

Program

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;
}

Compilation

I’m using the following compile options:

g++ -L/usr/lib -lboost_system -lboost_filesystem -lboost_thread -pthread -I/usr/include timer.cpp -o timer

Output

I’ve checked that the dynamic libraries exist and are located in the -L path. Here are the errors I’m getting:

/tmp/cc3hJrVk.o: In function `__static_initialization_and_destruction_0(int, int)':
timer.cpp:(.text+0xf0): undefined reference to `boost::system::generic_category()'
timer.cpp:(.text+0xfc): undefined reference to `boost::system::generic_category()'
timer.cpp:(.text+0x108): undefined reference to `boost::system::system_category()'
/tmp/cc3hJrVk.o: In function `boost::system::error_code::error_code()':
timer.cpp:(.text._ZN5boost6system10error_codeC2Ev[_ZN5boost6system10error_codeC5Ev]+0x17): undefined reference to `boost::system::system_category()'
/tmp/cc3hJrVk.o: In function `boost::asio::error::get_system_category()':
timer.cpp:(.text._ZN5boost4asio5error19get_system_categoryEv[boost::asio::error::get_system_category()]+0x5): undefined reference to `boost::system::system_category()'
collect2: ld returned 1 exit status

As you can see, it seems like the bugs are something you’d get if you’re improperly linking to libboost_system. I have two separate installs of boost that I’ve tested against, and I’m at my wit’s end.

Thanks in advance for any help!

Answer 1

You need to move all your libraries after the file names, at the end of the command.

Also: Boost::System must be built separately from the normal boost libraries. So if you haven’t built them separately they won’t exist.

See section 3 here:

http://www.boost.org/doc/libs/1_49_0/more/getting_started/unix-variants.html