Generate a perl module with a separate namespace using SWIG

问题

I need to generate a perl module Vinod::StatHandler. I have 2 files related to c++ code.(statHandler.h,statHandler.cpp)

Currently I am using the following command to generate the module.

swig -perl -noproxy -c++ -o StatHandler_wrap.cxx StatHandler.i

It generated the module StatHandler.pm

I generated the .so file using the following commands.

g++ -c statHandler.h statHandler.cpp -fPIC
g++ -O2 -shared -o StatHandler.so statHandler.o

I got the following error by just including "use StatHandler;" in a test Perl script.

Can't find 'boot_StatHandler' symbol in /home/vinod/cpp/swig//StatHandler.so 

LD_LIBRARY_PATH is set properly. I tried to go through the SWIG documentation and I didn't get much from it.

What should I specify in StatHandler.i file to generate the package "Vinod::StatHandler". Do I need to provide any other options for swig?

Contents of StatHandler.i:

%module "Vinod::StatHandler"
%{
#include "statHandler.h"
%}
#ifdef STATIC
%include perlmain.i
#endif

class StatHandler {
 StatHandler(string _dirName, string _statsFile):_statsDir(_dirName),_finalStatsFile(_statsFile){};
  void printStats();
 };

Contents of statHandler.h:

#ifndef STATHANDLER_H_
#define STATHANDLER_H_

#include<iostream>
#include<string.h>
#include<map>
#include<vector>

using namespace std;

class StatHandler {
 private:
  string _statsDir;
  string _finalStatsFile;
  vector<string> _statFiles;
  map <string, int> _dailyStats;
 public:
 StatHandler(string _dirName, string _statsFile):_statsDir(_dirName),_finalStatsFile(_statsFile){};
  bool getAllStatFiles();
  void extractStats();
  void printStats();
};

#endif

contents of StatHandlers.cpp:

#include <iostream>
#include "statHandler.h"
#include <sys/types.h>
#include <dirent.h>
#include <fstream>
#include <cstdlib>
using namespace std;


bool StatHandler::getAllStatFiles() {
  DIR* dirHandler;
  struct dirent* statsFile;
  if(dirHandler=opendir(_statsDir.c_str())){
    while(statsFile = readdir(dirHandler)){
      size_t size=strlen(statsFile->d_name);
      if(size>3) {
    char extension[4];
    memcpy(extension, &(statsFile->d_name[size-3]), 3);
    extension[3]='\0';
    if(strcmp(extension,".st") == 0) {
      _statFiles.push_back(_statsDir+statsFile->d_name);
    }
      }
    }
  } else {
    return false;
  }
  return true;
}


void StatHandler::extractStats() {
  getAllStatFiles();

  for(vector<string>::iterator fileIter=_statFiles.begin();fileIter!=_statFiles.end();++fileIter) {
    cout<<*(fileIter)<<"\n";
    ifstream in;
    in.open(fileIter->c_str(), ios::in);
    string term;
    while( in.is_open() && !getline(in, term, '\n').eof() ){
      size_t pos=0;
      if( (pos=term.find(" ")) != string::npos) {
    string keyword = term.substr(0,pos);
    string countStr=term.substr(pos+1);
    int count = atoi(countStr.c_str());
    if(_dailyStats.find(keyword) != _dailyStats.end()) {
      _dailyStats[keyword]+=count;
    } else {
       _dailyStats[keyword]=count;
    }
      }
      term.clear();
    }
    in.close();
  }  
}


void StatHandler::printStats() {
  ofstream out;
  out.open(_finalStatsFile.c_str(), ios::out);
  if(out) {
    for(map<string, int>::iterator statIter=_dailyStats.begin(); statIter!=_dailyStats.end();++statIter) {
      out<<statIter->first<<"\t"<<statIter->second<<"\n";
    }
    out.close();
  }

}


int main(int argc, char** argv) {
  StatHandler sh("/home/vinod/cpp/swig/","/home/vinod/cpp/swig/finalStats");
  sh.extractStats();
  sh.printStats();
  return 0;
}

回答1:

Actually, you forgot to compile the wrapper that gets generated by swig.

As stated in the SWIG Doc, you need to :

    swig -perl -noproxy -c++ -o StatHandler_wrap.cxx StatHandler.i
    g++ -c StatHandler.cpp -fPIC
    g++ -c StatHandler_wrap.cxx -I /usr/lib64/perl5/5.8.8/x86_64-linux-thread-multi/CORE -fPIC
    g++ -O2 -shared -o StatHandler.so StatHandler.o StatHandler_wrap.o

Then, provided you put the whole thing in the Vinod/ subdir, LD_LIBRARY_PATH="Vinod" perl -MVinod::StatHandler will works as expected.

NB: I edited the case and plural in your various files, as they were inconsistent.

来源：https://stackoverflow.com/questions/16146606/generate-a-perl-module-with-a-separate-namespace-using-swig