tcp_client.c

#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

#define PORT "8080"

int main() {
  struct addrinfo hints, *host;
  int sockfd, bytes;
  char buffer[BUFSIZ];

  // Configure server
  memset_s(&hints, sizeof(hints), 0, sizeof(hints));
  hints.ai_family = AF_INET6;
  hints.ai_socktype = SOCK_STREAM;

  // Fetch server info
  if (getaddrinfo(0, PORT, &hints, &host) < 0) {
    perror("Error getting server info");
    exit(1);
  }

  // Create socket
  sockfd = socket(host->ai_family, host->ai_socktype, host->ai_protocol);
  if (sockfd < 0) {
    perror("Error opening socket");
    exit(1);
  }

  // Connect
  if (connect(sockfd, host->ai_addr, host->ai_addrlen) < 0) {
    perror("Error connecting server");
    exit(1);
  }

  // Sending data
  const char *message = "Hello Server";
  if (send(sockfd, message, strlen(message), 0) == -1) {
    perror("Error sending data to server");
    exit(1);
  }

  // Receive data
  bytes = recv(sockfd, buffer, BUFSIZ, 0);
  if (bytes == -1) {
    perror("Error receiving data from server");
    exit(1);
  }

  buffer[bytes] = '\0';
  printf("SERVER>> %s\n", buffer);

  // Close
  freeaddrinfo(host);
  close(sockfd);

  return 0;
}