TCP Client in C++ for Linux and Windows.

#if defined(__WIN32)
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0600
#endif
#include <winsock2,h>
#include <ws2tcpip.h>
#pragma comment (lib, "ws2_32.lib")

#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <errno.h>

#endif

#include <stdio.h>
#include <string.h>

#if defined(_WIN32)
#define ISVALIDSOCKET(s) ((s) != INVALIV_SOCKET)
#define CLOSESOCKET(s) closesocket(s)
#define GETSOCKETERRNO()(WSAGetLastError())

#else
#define ISVALIDSOCKET(s) ((s) >= 0)
#define CLOSESOCKET(s) close(s)
#define GETSOCKETERRNO()(errno)
#define SOCKET int
#endif

#if defined(_WIN32)
#include <conio.h>
#endif

int main(int argc, char* argv[])
{   
    /// Initialize Windows socket
#if defined(_WIN32)
    WSADATA d;
    if (WSASartup(MAKEWORD(2, 2), &d)){
        fprintf(stderr, "Failed to initialize.\n");
        return 1;
    }
#endif
    /// Checn numberof arguments is corect or print the help string
    if (argc != 3){
        fprintf(stderr, "usage: tcp_client hostname port.\n");
    }
    /// Get socket information for houst address.
    printf("Configure remote adress...\n");
    struct addrinfo hints;
    memset(&hints, 0, sizeof(hints));
    hints.ai_socktype = SOCK_STREAM;
    struct addrinfo *peer_address;
    if (getaddrinfo(argv[1], argv[2], &hints, &peer_address)){
        fprintf(stderr, "getaddrinfo() failed. (%d)\n", GETSOCKETERRNO());
        return 1;
    }
    /// Print Socket information t screen
    printf("Remote address is: ");
    char address_buffer[100];
    char service_buffer[100];
    getnameinfo(peer_address->ai_addr, peer_address->ai_addrlen, 
        address_buffer, sizeof(address_buffer), 
        service_buffer, sizeof(service_buffer), NI_NUMERICHOST);
    printf("%s %s\n", address_buffer, service_buffer);

    /// Create socket.
    printf("Creating socket...\n");
    SOCKET socket_peer;
    socket_peer =socket(peer_address->ai_family, peer_address->ai_socktype, peer_address->ai_protocol);
    if (!ISVALIDSOCKET(socket_peer)){
        fprintf(stderr, "socket() failed (%d).\n", GETSOCKETERRNO());
        return 1;
    }

    /// Connect to peer.
    printf("Connecting...\n");
    if (connect(socket_peer, peer_address->ai_addr, peer_address->ai_addrlen)){
        fprintf(stderr, "connect() failed (%d).\n", GETSOCKETERRNO());
        return 1;
    }

    freeaddrinfo(peer_address); /// free the peer_address as we do not need any longer.

    printf("Connected.\n");
    printf("To send data enter text follow by enter.\n");

    /// The for ever client loop
    while(1){
        fd_set reads;
        FD_ZERO(&reads);
        FD_SET( socket_peer, &reads);
#if !defined(_WIN32)
        FD_SET(0, &reads);
#endif
        struct timeval timeout;
        timeout.tv_sec = 0;
        timeout.tv_usec = 100000;

        if (select(socket_peer+1, &reads, 0, 0, &timeout) < 0){
            fprintf(stderr, "select() failed. (%d)\n", GETSOCKETERRNO());
            return 1;
        } 

        if (FD_ISSET(socket_peer, &reads)){
            char read[4096];
            int bytes_received = recv(socket_peer, read, 4096, 0);
            if (bytes_received < 1){
                printf("Connection closed by peer.\n");
                break;
            }
            printf("Received (%d bytes): %s", bytes_received, read);
        }
#if defined(_WIN32)
        if (_kbhit()){
#else
        if (FD_ISSET(0, &reads)){
#endif
            char read[4096];
            if (!fgets(read, 4096, stdin))break;
            printf("Sending: %s", read);
            int bytes_send = send(socket_peer, read, strlen(read), 0);
            printf("Sent %d bytes.\n", bytes_send);
        }
    }/// while ends.

    printf("Close socket.\n");
    CLOSESOCKET(socket_peer);

#if defined(_WIN32)
    WSACleanup();
#endif

    printf("Finished.\n");
    return 0;
}