text: #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <netinet/in.h>
  
  void error(const char *msg) { perror(msg); exit(1); } // Error function used for reporting issues
  
  int main(int argc, char *argv[])
  {
  	int listenSocketFD, establishedConnectionFD, portNumber, charsRead;
  	socklen_t sizeOfClientInfo;
  	char buffer[256];
  	struct sockaddr_in serverAddress, clientAddress;
  
  	if (argc < 2) { fprintf(stderr,"USAGE: %s port\n", argv[0]); exit(1); } // Check usage & args
  
  	// Set up the address struct for this process (the server)
  	memset((char *)&serverAddress, '\0', sizeof(serverAddress)); // Clear out the address struct
  	portNumber = atoi(argv[1]); // Get the port number, convert to an integer from a string
  	serverAddress.sin_family = AF_INET; // Create a network-capable socket
  	serverAddress.sin_port = htons(portNumber); // Store the port number
  	serverAddress.sin_addr.s_addr = INADDR_ANY; // Any address is allowed for connection to this process
  
  	// Set up the socket
  	listenSocketFD = socket(AF_INET, SOCK_STREAM, 0); // Create the socket
  	if (listenSocketFD < 0) error("ERROR opening socket");
  
  	// Enable the socket to begin listening
  	if (bind(listenSocketFD, (struct sockaddr *)&serverAddress, sizeof(serverAddress)) < 0) // Connect socket to port
  		error("ERROR on binding");
  	listen(listenSocketFD, 5); // Flip the socket on - it can now receive up to 5 connections
  
  	// Accept a connection, blocking if one is not available until one connects
  	sizeOfClientInfo = sizeof(clientAddress); // Get the size of the address for the client that will connect
  	establishedConnectionFD = accept(listenSocketFD, (struct sockaddr *)&clientAddress, &sizeOfClientInfo); // Accept
  	if (establishedConnectionFD < 0) error("ERROR on accept");
  
  	// Get the message from the client and display it
  	memset(buffer, '\0', 256);
  	charsRead = recv(establishedConnectionFD, buffer, 255, 0); // Read the client's message from the socket
  	if (charsRead < 0) error("ERROR reading from socket");
  	printf("SERVER: I received this from the client: \"%s\"\n", buffer);
  
  	// Send a Success message back to the client
  	charsRead = send(establishedConnectionFD, "I am the server, and I got your message", 39, 0); // Send success back
  	if (charsRead < 0) error("ERROR writing to socket");
  	close(establishedConnectionFD); // Close the existing socket which is connected to the client
  	close(listenSocketFD); // Close the listening socket
  	return 0;
  }
  