Compile the first mathgl sample error - c++

a test file named ml.cc, I have already installed the mathgl headers to /usr/local/include and libmgl.a to /usr/local/lib
#include <mgl2/mgl.h>
int main()
{
mglGraph gr;
gr.FPlot("sin(pi*x)");
gr.WriteFrame("test.png");
return 0;
}
"g++ -c ml.cc" can work,but "g++ ml.cc" does not work,the error is
/tmp/ccPzPcZt.o: In function `mglGraph::mglGraph(int, int, int)':
ml.cc:(.text._ZN8mglGraphC2Eiii[_ZN8mglGraphC5Eiii]+0x3b): undefined reference to `mgl_create_graph_gl'
ml.cc:(.text._ZN8mglGraphC2Eiii[_ZN8mglGraphC5Eiii]+0x54): undefined reference to `mgl_create_graph'
/tmp/ccPzPcZt.o: In function `mglGraph::~mglGraph()':
ml.cc:(.text._ZN8mglGraphD2Ev[_ZN8mglGraphD5Ev]+0x28): undefined reference to `mgl_use_graph'
ml.cc:(.text._ZN8mglGraphD2Ev[_ZN8mglGraphD5Ev]+0x42): undefined reference to `mgl_delete_graph'
/tmp/ccPzPcZt.o: In function `mglGraph::SetFontSize(double)':
ml.cc:(.text._ZN8mglGraph11SetFontSizeEd[_ZN8mglGraph11SetFontSizeEd]+0x2a): undefined reference to `mgl_set_font_size'
/tmp/ccPzPcZt.o: In function `mglGraph::WriteFrame(char const*, char const*)':
ml.cc:(.text._ZN8mglGraph10WriteFrameEPKcS1_[_ZN8mglGraph10WriteFrameEPKcS1_]+0x2b): undefined reference to `mgl_write_frame'
/tmp/ccPzPcZt.o: In function `mglGraph::FPlot(char const*, char const*, char const*)':
ml.cc:(.text._ZN8mglGraph5FPlotEPKcS1_S1_[_ZN8mglGraph5FPlotEPKcS1_S1_]+0x30): undefined reference to `mgl_fplot'
collect2: error: ld returned 1 exit status
"g++ -L /usr/local/lib/ -l mgl ml.o" is the same error

I encoutered exactly the same problem and managed to solve it.
If you did the installation properly as you said. Then you simply need to add -lmgl AT THE END of the line! Like this:
g++ ml.o -lmgl
As luke already had mentioned, you have a linking error, thus compiling is not affected. Here is an explanation for this behaviour:
undefined reference to symbol even when nm indicates that this symbol is present in the shared library
Hope this solved your problem.
Peter

You have a linking error. To solve this you need to link against mgl. It looks like you are trying to, but its not working.
First, I would drop the space between the l and the mgl. so
g++ -L /usr/local/lib/ -lmgl ml.o
If that doesn't work, check to see if there are any other libraries you need to link against. See if g++ is throwing errors that it cannot find mgl.
Hope that helps.

Related

Is there a way to link JSONcpp library with C++ code?

I used the python amalmagate file to compile the json library. Now when I run the c++ code, I keep getting this error.
/usr/bin/ld: msort.cc:(.text+0x255): undefined reference to Json::Value::~Value()' /usr/bin/ld: msort.cc:(.text+0x264): undefined reference to Json::Value::~Value()'
/usr/bin/ld: msort.cc:(.text+0x278): undefined reference to Json::Value::operator[](int)' /usr/bin/ld: msort.cc:(.text+0x28c): undefined reference to Json::Value::Value(char const*)'
/usr/bin/ld: msort.cc:(.text+0x2a7): undefined reference to `Json::Value::get(char const*, Json::Value const&) const'
This is what I used to download the jsoncpp library
git clone https://github.com/open-source-parsers/jsoncpp.git
cd jsoncpp
python amalgamate.py
The code I ran to compile: g++ msort.cc -o msort
I understand that this means that the library is not connecting with my code. Any idea how I can fix this?
If you read the instructions for the amalgamated library you will see that you need to build with the library source file dist/jsoncpp.cpp:
g++ msort.cc dist/jsoncpp.cpp -o msort

How to recompile ntl and gmp libraries with "-fPIC" flag & make HELib as a shared library & undefined reference to func(std::ostream&) error

a C++ code built into a shared library for HELib is using NTL and GMP static library. But it gets following error:
/usr/bin/ld: /usr/local/lib/libntl.a(FFT.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
/usr/local/lib/libntl.a: error adding symbols: Bad value
collect2: error: ld returned 1 exit status
It was suggested int the post Click here
to recompile NTL and GMP with "-fPIC " flags.
I'am not able to find how I should do that.
Edit:
I'm able to build the shared library now after :
recompiling GMP and NTL by:
./configure --enable-shared
for gmp and
./configure SHARED=on
After make Install of HELib. I get error when I run the example codes.
The link to the Makefile : click to see makefile
Error:
g++ -g -O2 -std=c++11 -pthread -DFHE_THREADS -DFHE_BOOT_THREADS -DFHE_DCRT_THREADS -o Test_General_x Test_General.cpp -L/usr/local/lib -lntl -lgmp -lm -lfhe
/usr/local/lib/libfhe.so: undefined reference to write_raw_int(std::ostream&, long, long)'
/usr/local/lib/libfhe.so: undefined reference toread_raw_ZZ(std::istream&, NTL::ZZ&)'
/usr/local/lib/libfhe.so: undefined reference to void write_raw_vector<long>(std::ostream&, std::vector<long, std::allocator<long> > const&)'
/usr/local/lib/libfhe.so: undefined reference towriteEyeCatcher(std::ostream&, char const*)'
/usr/local/lib/libfhe.so: undefined reference to write_raw_xdouble(std::ostream&, NTL::xdouble)'
/usr/local/lib/libfhe.so: undefined reference toread_ntl_vec_long(std::istream&, NTL::Vec&)'
/usr/local/lib/libfhe.so: undefined reference to void read_raw_vector<long>(std::istream&, std::vector<long, std::allocator<long> >&)'
/usr/local/lib/libfhe.so: undefined reference toreadEyeCatcher(std::istream&, char const*)'
/usr/local/lib/libfhe.so: undefined reference to read_raw_int(std::istream&, long)'
/usr/local/lib/libfhe.so: undefined reference toread_raw_xdouble(std::istream&)'
/usr/local/lib/libfhe.so: undefined reference to write_raw_ZZ(std::ostream&, NTL::ZZ const&)'
/usr/local/lib/libfhe.so: undefined reference towrite_ntl_vec_long(std::ostream&, NTL::Vec const&, long)'
collect2: error: ld returned 1 exit status
Makefile:179: recipe for target 'Test_General_x' failed
make: *** [Test_General_x] Error 1
For NTL v11.5.1 atleast, doing ./configure --help | grep -i pic (as suggested in one of the comments for GMP) did not help at all - it found no matches. However, making a one line change in the file ntl-11.5.1/src/DoConfig (on line 17) from:
'CXXFLAGS' => '-g -O2'
to:
'CXXFLAGS' => '-g -O2 -fPIC',
solved the problem for me.
Marc Glisse provided the answer for the first two parts of the question.For the third part "Undefined Reference error" the answer is I'd not compiled and linked a x.cpp containing the functions that caused the undefined reference into my shared library. hence check : nm -CD /usr/local/lib/libfhe.so to see if these functions are listed with a linking address or not. If not then check which code provides this functionality. Link that code to the shared library.

boost/asio/ssl throwing "undefined reference" error

I am new to boost and am trying to compile the most basic program that includes boost/asio/ssl.
I am working on ubuntu 13.10 64bit and installed the latest boost like this:
sudo apt-get install boost-all-dev
Here is the magnificent code I am trying to compile:
#include <stdio.h>
#include <boost/asio/ssl/stream.hpp>
int main(){
printf("Hi\n");
return 0;
}
I googled and googled and the few hints I was able to find suggests I use some boost library flags. So I did:
g++ my_prog.cpp -o my_prog.bin -lboost_system -lboost_thread -lpthread
and all the time I get the same error message (no matter how many -l i shove in):
/tmp/cci6dJdZ.o: In function `boost::asio::ssl::detail::openssl_init_base::do_init::do_init()':
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initC2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initC5Ev]+0x2c): undefined reference to `SSL_library_init'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initC2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initC5Ev]+0x31): undefined reference to `SSL_load_error_strings'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initC2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initC5Ev]+0x36): undefined reference to `OPENSSL_add_all_algorithms_noconf'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initC2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initC5Ev]+0x47): undefined reference to `CRYPTO_num_locks'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initC2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initC5Ev]+0xcc): undefined reference to `CRYPTO_set_locking_callback'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initC2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initC5Ev]+0xd6): undefined reference to `CRYPTO_set_id_callback'
/tmp/cci6dJdZ.o: In function `boost::asio::ssl::detail::openssl_init_base::do_init::~do_init()':
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x13): undefined reference to `CRYPTO_set_id_callback'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x1d): undefined reference to `CRYPTO_set_locking_callback'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x22): undefined reference to `ERR_free_strings'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x2c): undefined reference to `ERR_remove_state'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x31): undefined reference to `EVP_cleanup'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x36): undefined reference to `CRYPTO_cleanup_all_ex_data'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x40): undefined reference to `CONF_modules_unload'
my_prog.cpp:(.text._ZN5boost4asio3ssl6detail17openssl_init_base7do_initD2Ev[_ZN5boost4asio3ssl6detail17openssl_init_base7do_initD5Ev]+0x45): undefined reference to `ENGINE_cleanup'
/tmp/cci6dJdZ.o: In function `boost::asio::error::detail::ssl_category::message(int) const':
my_prog.cpp:(.text._ZNK5boost4asio5error6detail12ssl_category7messageEi[_ZNK5boost4asio5error6detail12ssl_category7messageEi]+0x1d): undefined reference to `ERR_reason_error_string'
collect2: error: ld returned 1 exit status
Or in short: it complaining about missing symbols like:
undefined reference to `SSL_library_init'
or:
undefined reference to `ERR_reason_error_string'.
Another funny fact is that if I change the include:
#include <boost/asio/ssl/stream.hpp>
for example to
#include <boost/asio/ssl/stream_base.hpp>
it compiles just fine (even without -lboost_system and all others..).
I spent a whole day on this and still can't for the life of me figure this out.
Any ideas guys?
In vs2013, when I include <boost/asio/ssl.hpp> I see
unresolved external symbol _CONF_modules_upload
unresolved external symbol _ERR_reason_error_string
I solved those issues by adding
libcrypto32MD.lib
in Linker/Additional Dependencies

Linking issues with wxWidget sample on Ubuntu 12.04 (amd64)

I have a problem linking the wxWidget sample application (http://www.wxwidgets.org/docs/tutorials/hello.htm) with is stored in main.cpp. I try to compile and link it using:
g++ `wx-config --cxxflags --libs` main.cpp
The output I get is the following:
/tmp/ccFHWUaX.o: In function `wxCreateApp()':
main.cpp:(.text+0x31): undefined reference to `wxAppConsole::CheckBuildOptions(char const*, char const*)'
/tmp/ccFHWUaX.o: In function `main':
main.cpp:(.text+0x91): undefined reference to `wxEntry(int&, char**)'
/tmp/ccFHWUaX.o: In function `MyFrame::MyFrame(wxString const&, wxPoint const&, wxSize const&)':
main.cpp:(.text+0x1d2): undefined reference to `wxFrameNameStr'
main.cpp:(.text+0x267): undefined reference to `wxEmptyString'
main.cpp:(.text+0x2ea): undefined reference to `wxEmptyString'
main.cpp:(.text+0x366): undefined reference to `wxMenuBar::wxMenuBar()'
main.cpp:(.text+0x3d1): undefined reference to `wxFrameBase::SetMenuBar(wxMenuBar*)'
main.cpp:(.text+0x3da): undefined reference to `wxStatusLineNameStr'
main.cpp:(.text+0x407): undefined reference to `wxFrame::CreateStatusBar(int, long, int, wxString const&)'
main.cpp:(.text+0x44f): undefined reference to `wxFrameBase::SetStatusText(wxString const&, int)'
main.cpp:(.text+0x533): undefined reference to `wxFrame::~wxFrame()'
(and many lines more...)
WxWidgets-2.8 is installed using the ubuntu repository and its libs are located in /usr/lib/x86_64-linux-gnu. I also tried to build specifying the library path with:
-L/usr/lib/x86_64-linux-gnu/
but, this does not change the output. I was blaming multiarch for my problem, but actually only as I don't know how it works exactly.
Can someone tell me how to build the sample correctly?
Thank you
Michael
When using static linking, the libraries must always come after the object files using the symbols from them, otherwise they're simply ignored by the linker as they're not needed at the moment when it first sees them. So us2012 is correct, you need to put wx-config part after your source file.
You could also use shared wxWidgets libraries, then the order wouldn't matter. But it's still a good habit to use the right order, which works for both static and shared libraries, anyhow.

gnuplot-iostream not linking to boost

Hi I'm trying to use gnuplot-iostream, at the minute I'm just trying to get the code here working. When I try to combile I get errors in the linker saying:
In function `stream<int, boost::iostreams::file_descriptor_flags>':
/usr/include/boost/iostreams/stream.hpp:130: undefined reference to `boost::iostreams::file_descriptor_sink::file_descriptor_sink(int, boost::iostreams::file_descriptor_flags)'
In function `boost::iostreams::file_descriptor_sink boost::iostreams::detail::wrap<boost::iostreams::file_descriptor_sink>(boost::iostreams::file_descriptor_sink const&, boost::disable_if<boost::iostreams::is_std_io<boost::iostreams::file_descriptor_sink>, void>::type*)':
/usr/include/boost/iostreams/detail/wrap_unwrap.hpp:53: undefined reference to `boost::iostreams::file_descriptor_sink::file_descriptor_sink(boost::iostreams::file_descriptor_sink const&)'
In function `concept_adapter':
/usr/include/boost/iostreams/detail/adapter/concept_adapter.hpp:67: undefined reference to `boost::iostreams::file_descriptor_sink::file_descriptor_sink(boost::iostreams::file_descriptor_sink const&)'
/usr/include/boost/iostreams/detail/adapter/concept_adapter.hpp:38: undefined reference to `boost::iostreams::file_descriptor_sink::file_descriptor_sink(boost::iostreams::file_descriptor_sink const&)'
In function `long boost::iostreams::detail::write_device_impl<boost::iostreams::output>::write<boost::iostreams::file_descriptor_sink>(boost::iostreams::file_descriptor_sink&, boost::iostreams::char_type_of<boost::iostreams::file_descriptor_sink>::type const*, long)':
/usr/include/boost/iostreams/write.hpp:121: undefined reference to `boost::iostreams::file_descriptor::write(char const*, long)'
In function `void boost::iostreams::detail::close_impl<boost::iostreams::closable_tag>::close<boost::iostreams::file_descriptor_sink>(boost::iostreams::file_descriptor_sink&, std::_Ios_Openmode)':
/usr/include/boost/iostreams/close.hpp:224: undefined reference to `boost::iostreams::file_descriptor::close()'
In function `std::fpos<__mbstate_t> boost::iostreams::detail::seek_device_impl<boost::iostreams::any_tag>::seek<boost::iostreams::file_descriptor_sink>(boost::iostreams::file_descriptor_sink&, long, std::_Ios_Seekdir, std::_Ios_Openmode)':
/usr/include/boost/iostreams/seek.hpp:137: undefined reference to `boost::iostreams::file_descriptor::seek(long, std::_Ios_Seekdir)'
collect2: ld returned 1 exit status
Note I have boost installed and have previously compiled programs that use iostream.
Any help massively appreciated. Thanks
Ruling out the obvious... are you compiling with g++ -lboost_iostreams? If you can share some information about how the compiler and linker are being invoked it will make it easier to answer your question.
Run into exact problem when tried to use g++ with gnuplot-iostream library.
g++ prog.cpp -L/usr/lib -lboost_filesystem -lboost_system -lboost_iostreams
Resolved the issue for me - the code were compiled successfully with no errors.