Message Client Example

• Open a message queue with the given KEY.

• Output a message and exit the program in case of failure.

• Read the message body from the keyboard and set the other parameters of msg_1_t.

• Send msg_1_t message to the queue.

• Wait for msg_2_t and print it.

• Send msg_1_t confirmation.

message-client.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include "message-types.h"

int main(int argc, char ** argv)
{
  int msgid = msgget(KEY, 0666);
  if(msgid == -1)
  {
    printf("Error msgget.\n");
    return EXIT_FAILURE;
  }

  int i = 0;
  struct msg_1_t message1;
  while( (i < (MAXLEN - 1)) &&
         ((message1.body[i++] = getchar()) != '\n') );
  message1.body[i] = '\0';
  message1.mtype = 1;
  message1.snd_pid = getpid();
  msgsnd(msgid, &message1, sizeof(struct msg_1_t), 0);
  printf("Sended: %s\n", message1.body);

  struct msg_2_t message2;
  msgrcv(msgid, &message2, sizeof(struct msg_2_t), 2, 0);
  printf("Server [pid = %i] responded: %s\n", message2.snd_pid, message2.body);

  message1.mtype = 1;
  msgsnd(msgid, &message1, sizeof(struct msg_1_t), 0);

  return EXIT_SUCCESS;
}