Sockets

#include <iostream>
#include <thread>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <fstream>
#include <vector>
#include <sstream>

using namespace std;

void error(const char* msg)
{
    perror(msg);
    exit(1);
}

void client()
{
    int sock, n;
    unsigned int length;
    struct sockaddr_in server, from, local;
    char* buffer = "Client message\n";
    char bufferFrom[256];

    bzero(bufferFrom, 256);

    sock = socket(AF_INET, SOCK_DGRAM, 0);
    if (sock < 0)
        error("Socket");

    local.sin_family = AF_INET;
    local.sin_addr.s_addr = inet_addr("10.0.0.21");
    local.sin_port = htons(25025);

    server.sin_family = AF_INET;
    server.sin_port = htons(25025);

    length = sizeof(struct sockaddr_in);

    int reuse = 1;
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuse, sizeof(reuse)) < 0)
        perror("setsockopt(SO_REUSEADDR) failed");

    #ifdef SO_REUSEPORT
        if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (const char*)&reuse, sizeof(reuse)) < 0)
            perror("setsockopt(SO_REUSEPORT) failed");
    #endif

    if (bind(sock, (struct sockaddr *)&local, length) < 0)
        perror("binding");


    // Get the IPs
    ifstream file;
    stringstream ss;
    vector<string> ips;
    file.exceptions( ifstream::failbit | ifstream::badbit );
    try
    {
        file.open("ips.txt");
        while (!file.eof())
        {
            string ip;
            file >> ip;
            ips.push_back(ip);
        }
        file.close();
    } catch(const ofstream::failure& e)
    {
        cerr << "Exception opening/reading file: " << e.what() << endl;
    }

    if (ips.empty())
    {
        cerr << "No ips" << endl;
        close(sock);
        return;
    }

    for (size_t i = 0; i < ips.size(); i++)
    {
        cout << i << ") Sending message to: " << ips[i] << endl;
        server.sin_addr.s_addr = inet_addr(ips[i].c_str());
        n = sendto(sock, buffer, strlen(buffer), 0, (const struct sockaddr *)&server, length);
        if (n < 0)
        {
            perror("Sendto");
            return;
        }
    }
    close(sock);
}

int main()
{
    thread clientThread(client);

    clientThread.join();

    return 0;
}