This is a very basic question, I only post because I've spent already some time into it. This is what I've done so far:
Downloaded and compiled the boost library:
sudo ./bootstrap.sh and sudo ./bjam install
This way it was installed into /usr/local/lib.
In my source code I've added only:
#include <boost/asio.hpp>
using boost::asio::ip::tcp
I compile it with:
g++ -I/usr/lib/jvm/java-6-openjdk/include -L/usr/local/lib -fPIC -lboost_system -shared -o libagent.so agent.cpp
However, ldd -d ./libagent.so gives me:
libboost_system.so.1.46.1 => not found
But there is no error thrown, when using the -lboost_system and ls /usr/local/lib gets me among other things:
libboost_system.so
libboost_system.a
What am I missing?
Did the ./bjam install tool also run the ldconfig(8) tool? ldconfig(8) needs to be run after new libraries are installed to update the caches used by ld.so(8) at program execution time.
You should compile it with:
g++ -I/usr/lib/jvm/java-6-openjdk/include -L/usr/local/lib -Wl,-rpath,/usr/local/lib -fPIC -lboost_system -shared -o libagent.so agent.cpp
This makes it look for the boost library in /usr/local/lib at runtime, the -L option only makes it look in /usr/local/lib at compile time.
Related
I am using boost/multiprecision/cpp_int.hpp within class of a cpp file boost.cpp
My main in in practice.cpp
How do i add the Boost into the make file
The current make file looks like this:
practice.exe : practice.o
g++ -Wall -O2 practice.cpp -lws2_32 -o practice.exe
practice.o : practice.cpp
g++ -c -O2 -Wall practice.cpp
clean:
del *.o
del *.exe
So, the general idea is to just system install boost and let the compiler find it in the default include paths.
E.g. on a debian
apt install libboost-all-dev
Should be enough. Boost Multiprecision itself is header-only. So if you only need cpp_int, cpp_dec_float and cpp_bin_float, you're done. You might want GMP/MPFR support, in which case you need to link those libraries with the additional linker flags -lgmp or -lmpfr.
If you need Serialization support, also link -lboost_serialization which would be installed in the default library paths with the system-wide Boost package we installed at the start.
I'm trying to use X86_64-w64-mingw32-g++ (packaged in Archlinux's MingW package) to cross compile some C++ code into an Windows executable, however I'm having trouble getting past some issues.
I'm calling
x86_64-w64-mingw32-g++ -o build_win/asm build_win/asm.o build_win/asm_lib.o build_win/socket_boost.o -I../extra/etc -fopenmp -lrt -std=c++11 -g -lboost_system -lboost_serialization
from a makefile, but I get thrown the errors:
/usr/lib/gcc/x86_64-w64-mingw32/5.1.0/../../../../x86_64-w64-mingw32/bin/ld: cannot find -lrt
/usr/lib/gcc/x86_64-w64-mingw32/5.1.0/../../../../x86_64-w64-mingw32/bin/ld: cannot find -lboost_system
/usr/lib/gcc/x86_64-w64-mingw32/5.1.0/../../../../x86_64-w64-mingw32/bin/ld: cannot find -lboost_serialization
This works fine with native g++, so exactly do I have to change for mingw to compile?
EDIT: I have mingw-w64-boost package installed, which includes boost libraries pre-compiled and ready to be linked. However, it seems the naming convention is a bit different, and -lboost_system for example becomes -llibboost_system-mt (not exactly sure what the -mt suffix entails).
Problem is I can't find the mingw counterpart for -lrt. I've tried with both -lrtm and -lrtutils but in both cases I get:
[...]
undefined reference to `__imp_getsockopt'
Are you sure that -lboost_system and other libraries are present in the same directory as makefile ?
If not then please include -L flag which indicates the location of your library.
For example:
-L /path_openmp -fopenmp -L /path_boost_system/ -lboost_system -L /path_serialization -lboost_serialization
Moreover, you need not include -I and -g flag when creating an executable from .o files. These are needed when you create .o from .cpp files.
There is no rt library on Windows.
You are missing -lws2_32.
$ x86_64-w64-mingw32-nm -A /usr/x86_64-w64-mingw32/lib/*.a 2>/dev/null | grep getsockopt | grep " T "
I'm trying to write an autoconf test for a C++ library. I followed http://nerdland.net/2009/07/detecting-c-libraries-with-autotools/ . My check looks like this:
SAVED_LDFLAGS=$LDFLAGS
LDFLAGS="$LDFLAGS -lMyLib"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM([#include <mylibheader.hpp>],
[MyLibNamespace::SomeObject obj()])],
[TEST_LIBS="$TEST_LIBS -lMyLib"] [HAVE_MYLIB=1],
[AC_MSG_ERROR([libMyLib is not installed.])])
LDFLAGS=$SAVED_LDFLAGS
The test fails. If i check config.log the problem seems to be with the generated compilation command given by autoconf for the check:
g++ -o conftest -g -O2 -lMyLib conftest.cpp
As you can see, the -l params aren't at the end, after all inputs and outpus. If i copy&paste the conftest.cpp code from config.log i can make it compile with:
g++ -o conftest -g -O2 conftest.cpp -lMyLib
How can autoconf be wrong? How may i fix this?
The problem is that you're adding -lMyLib to LDFLAGS instead of adding to LIBS. In other words, do this instead:
SAVED_LIBS=$LIBS
LIBS="-lMyLib $LIBS"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM([#include <mylibheader.hpp>],
[MyLibNamespace::SomeObject obj()])],
[TEST_LIBS="$TEST_LIBS -lMyLib"] [HAVE_MYLIB=1],
[AC_MSG_ERROR([libMyLib is not installed.])])
LIBS=$SAVED_LIBS
Edit: link order of libraries is important, so I've updated the LIBS= line to link MyLib before the other libraries, if any, with the assumption that MyLib may depend on other libraries.
I would like to create a dynamic library for c++ program on linux.
In c++ program/system I`m using libconfig++ library, libpqxx library, some boost and c++11.
My steps:
1)
g++ -Wall -I/usr/local/include/ -std=c++0x -lconfig++ -Wall -lpqxx -lpq -fPIC -c ../SourceFiles/DBHandler.cpp ../SourceFiles/ParamServer.cpp ../SourceFiles/Functions.cpp
2)
g++ -shared -Wl,-soname,libctest.so.1 -o libctest.so.1.0 *.o
3)
ln -sf libctest.so.1.0 libctest.so.1
4)
ln -sf libctest.so.1.0 libctest.so
5) compile
g++ -Wall -I/path/to/include-files -L/path/to/libraries program.cpp -I/usr/local/include/ -std=c++0x -lconfig++ -lpqxx -lpq -lctest -o prog
After execute above command :
/usr/bin/ld: cannot find -lctest
collect2: ld returned 1 exit status
What am I doing wrong?
Here is the reference:
enter link description here
In step 5, you forgot -L. to look for libraries in the current directory.
By default, only a [long] list of system directories is used when searching for libraries.
You will also need to add . to the LD_LIBRARY_PATH environment variable before executing your program, so that the current directory is searched at runtime, too. Running ldconfig will avoid this, but if you are only testing your library and do not want to persistently affect your system, I would stick to the LD_LIBRARY_PATH approach.
An alternative is to "install" your library into one of those directories, such as /usr/local/lib (or your equivalent). You should use ldconfig after doing this, so that the dynamic library cache and all your symlinks are set up for you. This is the canonical approach but may not be suitable during iterative development of said library.
You need to ldconfig update the dynamic library cache -- it will also create the symbolic links for you.
See eg Section 3.5 of this Linux Documentation Project HOWTO
I've been trying to go through Boost tutorials but I got stuck at linking the filesystem library.
I have Ubuntu 12.10. Installation wasn't that hard
sudo apt-get install libboost-all-dev
This put all headers in /usr/local/include and compiled sources in /usr/lib/
[--headers]
[--binaries]
I wrote this program [--program]. When I tried to compiled it
g++ -g tut1.cpp -o tut1 -lboost_system -lboost_filesystem
got this errors: [--errors].
After a little search on http://www.boost.org/doc/libs/1_53_0/more/getting_started/unix-variants.html
I tried this:
g++ -g -I /usr/local/include/boost/ tut1.cpp -o tut1 -L /usr/lib/libboost_filesystem.a -lboost_system -lboost_filesystem
but didn't have luck. I had the same errors.
Since I cannot put more than 2 links in the post, here are all links
http://pastebin.com/DakVFn12
I found the answer myself here:
http://www.richelbilderbeek.nl/CppLinkErrorUndefinedReferenceToBoostFilesystemDetailGet_current_path_api.htm
Looks like binaries weren't in /usr/lib but in /usr/local/lib.
So the correct command for compilation would be:
g++ -g tut1.cpp -o tut1 -L/usr/local/lib/ -lboost_filesystem
#Yuushi, that was 1 problem.
The -L command should be the base path where the libraries are contained, not the path to a specific library. Try with -L /usr/lib/ instead.