Octave sample code failing to compile in g++?

Question

I'm attempting to get the Octave C++ code here to compile in g++ (Ubuntu/Linaro 4.6.4-1ubuntu1~12.04) 4.6.4).

This trimmed version of the above will compile in g++:

#include <iostream>
#include <octave/oct.h>
using namespace std;

int main() {
//  Matrix L=Matrix(2,2);

  return 0;
}

but if I unremark out the line Matrix L=Matrix(2,2); then compile with g++ temp.cpp it gives the error message:

/tmp/ccTa3Am5.o: In function `Array2<double>::~Array2()':
temp.cpp:(.text._ZN6Array2IdED2Ev[_ZN6Array2IdED5Ev]+0x1f): undefined reference to `Array<double>::~Array()'
/tmp/ccTa3Am5.o: In function `Array<double>::Array(dim_vector const&)':
temp.cpp:(.text._ZN5ArrayIdEC2ERK10dim_vector[_ZN5ArrayIdEC5ERK10dim_vector]+0x26): undefined reference to `Array<double>::get_size(dim_vector const&)'
/tmp/ccTa3Am5.o:(.rodata._ZTV5ArrayIdE[vtable for Array<double>]+0x10): undefined reference to `Array<double>::~Array()'
/tmp/ccTa3Am5.o:(.rodata._ZTV5ArrayIdE[vtable for Array<double>]+0x18): undefined reference to `Array<double>::~Array()'
collect2: ld returned 1 exit status

I'm unsure why. Perhaps I'm missing an #include, perhaps I don't have an appropriate file installed, perhaps I'm not linking to the appropriate library, or perhaps I'm misusing Octave in some way.

Question: Why is this failing to compile? How can I fix it?

It compiles fine if I use mkoctfile --link-stand-alone temp.cpp as indicated at the above site, however, I'd like to use g++ if possible, since I eventually want to be able to call Octave functions from another program I've written in C++.

Maybe you should have a look at [Howto Use Octave Functions in C/C++ Programs](http://www.mathias-michel.de/download/howto-octave-c%2B%2B.ps), which provides some useful information about how to compile C/C++ code with octave included. On Page 2 you will find an example of how to compile such a program using g++ — sebi, Sep 03 '13 at 13:06
It's not failing to compile, all of those are linker errors. — Ben Voigt, Sep 03 '13 at 13:38

score 1 · Answer 1 · answered Sep 03 '13 at 13:01

1

You need to link to the octave library. If the library is octave.a:

g++ -loctave temp.cpp

answered Sep 03 '13 at 13:01

Appleshell

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1

Not that easy - you should let the `mkoctfile` do the linking for you when working with Octave in C/C++. Can save you a lot of headaches ;) – sebi Sep 03 '13 at 13:11

score 1 · Accepted Answer · answered Sep 03 '13 at 13:16

As indicated in my comment a simple example can be found in this Howto. So in your case a simple way to achieve compilation will be creating a makefile as follows:

makefile:
all: temp

clean:
    -rm temp.o temp

temp: temp.o
      mkoctfile --link-stand-alone -o temp temp.o

temp.o: temp.cpp
        g++ -c -I$(OCTAVE_INCLUDE)
        -I$(OCTAVE_INCLUDE)octave -o temp.o temp.cpp

$(OCTAVE_INCLUDE) is an environment variable that should be set to your octave include path (e.g. /usr/include/octave-x.x.xx). Then you can simply compile and link your test application using the command make all.

This works for me (but we need tabs in the Makefile, instead of spaces, before commands). — Douglas S. Stones, Sep 03 '13 at 13:34

score 0 · Answer 3 · edited May 23 '17 at 10:29

Add the library directories to your link command:

your-local-path\octave-x.x.xx\lib\
your-local-path\octave-x.x.xx\lib\octave\x.x.xx\

mkoctfile -L"\your-path\octave-x.x.xx\lib" -L"\your-path\octave-x.x.x\lib\octave\x.x.xx" --link-stand-alone temp.cpp

For cxx11 linker errors:
Converting std::__cxx11::string to std::string

"If you get linker errors about undefined references to symbols that involve types in the std::__cxx11 namespace or the tag [abi:cxx11] then it probably indicates that you are trying to link together object files that were compiled with different values for the _GLIBCXX_USE_CXX11_ABI macro. This commonly happens when linking to a third-party library that was compiled with an older version of GCC."

Defining the following macro before including any standard library headers should fix your problem:

#define _GLIBCXX_USE_CXX11_ABI 0

Octave sample code failing to compile in g++?

3 Answers3