On September 4, 2016 11:12:06 AM GMT+02:00, Hermann Norpois <hnorpois@gmail.com> wrote:
Hello,
I just started with boost and it is obvious that I do not understand give my compiler (not mentioning code::blocks) the correct instructions.
I installed boost_1_61_0 on Ubuntu 14.04 and followed the instruction. So I did (as root after sudo -i) in the directory of boost_1_61_0. I use g++4.9. It was the same with g++4.8.
1) ./bootstrap.sh prefix=/usr/local
2) ./b2 install
So the libs are: /usr/local/lib
The headers: /usr/include/boost
Are you sure those are not the system's boost headers? With the prefix set above I expect them to live at /usr/local/include/boost Make sure you don't accidentally mix your custom boost installation's libraries with the system's boost headers. Using gcc/clang use -I for setting include paths and -L for library paths.
Actually I was interested in some stuff with asio. So I started with this code from the tutorial. http://www.boost.org/doc/libs/1_61_0/doc/html/boost_asio/tutorial/tutdaytime...
g++ -Wall main.cpp -o zclient /tmp/ccxx7PrW.o: In Funktion `__static_initialization_and_destruction_0(int, int)': main.cpp:(.text+0x52e): Nicht definierter Verweis auf `boost::system::generic_category()' main.cpp:(.text+0x53a): Nicht definierter Verweis auf `boost::system::generic_category()' main.cpp:(.text+0x546): Nicht definierter Verweis auf `boost::system::system_category()' /tmp/ccxx7PrW.o: In Funktion `boost::system::error_code::error_code()': main.cpp:(.text._ZN5boost6system10error_codeC2Ev[_ZN5boost6system10error_codeC5Ev]+0x17): Nicht definierter Verweis auf `boost::system::system_category()' /tmp/ccxx7PrW.o: In Funktion `boost::asio::error::get_system_category()': main.cpp:(.text._ZN5boost4asio5error19get_system_categoryEv[_ZN5boost4asio5error19get_system_categoryEv]+0x5): Nicht definierter Verweis auf `boost::system::system_category()' /tmp/ccxx7PrW.o: In Funktion `boost::asio::detail::posix_thread::~posix_thread()': main.cpp:(.text._ZN5boost4asio6detail12posix_threadD2Ev[_ZN5boost4asio6detail12posix_threadD5Ev]+0x26): Nicht definierter Verweis auf `pthread_detach' /tmp/ccxx7PrW.o: In Funktion `boost::asio::detail::posix_thread::join()': main.cpp:(.text._ZN5boost4asio6detail12posix_thread4joinEv[_ZN5boost4asio6detail12posix_thread4joinEv]+0x2b): Nicht definierter Verweis auf `pthread_join' /tmp/ccxx7PrW.o: In Funktion `boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)': main.cpp:(.text._ZN5boost4asio6detail12posix_thread12start_threadEPNS2_9func_baseE[_ZN5boost4asio6detail12posix_thread12start_threadEPNS2_9func_baseE]+0x29): Nicht definierter Verweis auf `pthread_create' collect2: error: ld returned 1 exit status
Those are (localized) undefined reference linker errors. If you carefully read them, your linker is unable to find boost system symbols. Link with -lboost_system to fix this.
I have to add that the simple programm in the starting guide worked properly http://www.boost.org/doc/libs/1_61_0/more/getting_started/unix-variants.html...
via g++ -Wall main.cpp -o zu
It worked in Code::Blocks as well (without any additional information).
Even the second simple programm (same link) I managed to compile giving the full path: g++ -Wall main.cpp -o extractmail /usr/local/lib/libboost_regex.a
At no time I had not to instruct the compiler about the headers. I was wondering. So it must have anything to do with the libs.
Coming back to my asio- example. Do I need libs for it? I guess is has something to do with the expression -lboost_system. I used it without understanding it. But it did not help.
Actually I would appreciate if was able to use Code::Blocks but I did not manage to give Code::Blocks the correct instructions. I
found some hints, at least amounts of hints ... But it did not work at all.
If somebody is able to explain it (for idiots) ... This would be great.
For gcc/clang -I path/to/local/boost/headers sets include paths to look for headers -L path/to/local/boost/libraries sets library paths to look for libraries -lboost_system links libboost_system to your program (note: upper case i vs lower case L above) I'm sure you'll find an equivalent in Code::Blocks.
Thanks
Hermann
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