Question

I’m creating a small program with some design patterns, and I’m trying to implement a singleton. In this singleton class I have a vector containing a File object which I defined myself.

Now, when doing the actual push_back, I get a segmentation fault. I tried removing the singleton pattern and the push_back worked great. I’ve read on a forum that the problem might be cause by the vector not being initialized yet. Is their a way that would allow me to use my vector and my singleton pattern without causing a segmentation fault?

EDIT:

header:

class FileManager
{
public:
    static FileManager* GetManager();
    ~FileManager();

    void InitManager();

    void LoadAllTitle();

private:
    FileManager();
    static FileManager* _fileManager;

    std::vector<File> _files;
};

source:

//C++ Header
#include <iostream>

//C Header

//local header
#include "filemanager.h"
#include "settings.h"
#include "defs.h"
#include "file.h"
#include "utilities.h"

FileManager* FileManager::_fileManager = NULL;

FileManager* FileManager::GetManager()
{
    if( _fileManager )
    {
        _fileManager = new FileManager();
    }

    return( _fileManager );
}

FileManager::FileManager()
{
}

FileManager::~FileManager()
{
}

void FileManager::InitManager()
{
    int numberOfFile = Settings::GetSettings()->NumberOfFile() + 1;
    for( unsigned int i = 1; i < numberOfFile; i++ )
    {
        std::string path = "data/data";
        path += IntToStr( i );
        path += ".ndb";

        File tempFile( path );

        _files.push_back( tempFile );  // segmentation fault
    }

    printf( " Done...\n" ); 
}

void FileManager::LoadAllTitle()
{
    int numberOfFile = Settings::GetSettings()->NumberOfFile() + 1;
    std::string titles = "ALL TITLES: \n";

    for( unsigned int i = 1; i < numberOfFile; i++ )
    {
        titles += _files[i].ReadTitle();
        titles += "\n";
    }
}

And here is the call I make in main.cpp

FileManager::GetManager()->InitManager();

The thing is if I place my constructor in public and do this in the main:

FileManager fm;
fm.InitManager();

this doesn’t return a segmentation fault

Answer 1

Your logic is backwards – if (_fileManager) should be if (!_fileManager).