An experiment in file writing.

test.cpp

/**
 *
 *  Experiment: Trying to see how an output file could possibly be corrupted
 *  by failed program....
 *
 *
 *  e.g. https://trello.com/c/7F9VWd2s/980-error-in-vincsv-from-the-logger
 *
 *  Experiment:
 *
 *  1. Start multiple processes: ./test a,  ./test b
 *  2. Let them run for a couple of seconds.
 *  3. Kill process b, then kill process a.
 *  4. The output file will have data from both processes.
 *
 */
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <unistd.h>


unsigned int RECORDS = 100;
unsigned int SLEEP = 100000;  // in microseconds

using namespace std;


void output(ofstream *fs, string value, int i, string process) {
    ostringstream ss;
    ss << process << ": [[ " << value << " / " << value << ": " << i << " ]]" << endl;
    *fs << ss.str();
    fs->flush();
}


int main(int argc, char *argv[]) {

    if(argc != 2) {
        cout << "USAGE: ./test <foo>" << endl;
        return 1;
    }

    int i = 0;
    string proc = argv[1];
    ofstream fs;

    string filename = "output.txt";

    cout << "Starting..." << endl;

    fs.open(filename.c_str(), fstream::out);

    cout << "Opened file: " << filename.c_str() << endl;
    while(i < RECORDS) {
        output(&fs, "testing", i, proc);
        cout << "Wrote record " << i << endl;
        i++;
        usleep(SLEEP);
    }

    fs.close();
    cout << "...done." << endl;
    return 0;
}

So you're thinking the logger is running multiple instances and thus writing to the file multiple times?