Swig Perl: wrong ELF class

问题

I am trying to build a Perl module out of a CXX module using Swig. There are multiple guides related to this:

The generic Swig tutorial with a Perl section
The Swig and C++ guide
The Swig and Perl5 guide

I'm new to Swig and not very familiar with C(++), but I've been able to compile my module following the tutorial in 1:

I created an interface file:

%module my_module

%{
    #include "case.h"
    #include "case.h"
    #include "lexindex.h"
    #include "intlist.h"
    #include "weight.h"
    #include "invindex.h"
    #include "winnow.h"
    #include "nbayes.h"
    #include "svmclass.h"
    #include "svm.h"
    #include "sockhelp.h"
    #include "strtok_r.h"
    extern int num_features_guess;
    void StopServerFun( int Signal );
%}
extern int num_features_guess;

class Case {
public:
    Case();
    ~Case();
};

class Feature {
public:
    Feature();
    ~Feature();
};

I run Swig:

swig -c++ -perl5 my_module.i

This generates the file my_module_wrap.cxx. I compile:

g++ -c `perl -MConfig -e 'print join(" ", @Config{qw(ccflags optimize cccdlflags)}, "-I$Config{archlib}/CORE")'` my_module.cxx my_module_wrap.cxx

And subsequently:

g++ `perl -MConfig -e 'print $Config{lddlflags}'` my_module.o my_module_wrap.o -o my_module.so

As expected, this does create the file my_module.so.

Then I try to use it like this:

$ perl
use my_module;

This results in the following error:

Can't load './my_module.so' for module my_module: ./my_module.so: wrong ELF class: ELFCLASS64 at /usr/net/ActivePerl-5.14.2.1402/lib/DynaLoader.pm line 191.

As you can see from the error message, I use ActivePerl v5.14. According to the documentation, Swig should support Perl version >=5.8. Otherwise, I do not see where to dig deeper.

There is a similar question about Python, but this was a user fault using different Python interpreters.

回答1:

Can't load './my_module.so' for module my_module: ./my_module.so: wrong ELF class: ELFCLASS64

This means: you are trying to load 64-bit my_module.so into a 32-bit perl process.

You must either use 64-bit perl, or rebuild my_module.so as a 32-bit shared library (by adding -m32 to compile and link commands).

来源：https://stackoverflow.com/questions/51382757/swig-perl-wrong-elf-class

标签

c++

perl

swig

elf