status.c

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

#define SIZE 4096

int main(int argc, char* argv[]) {
  int status = 200;

  int len;
    int sock;
    struct hostent *host;
    struct sockaddr_in server;

  char buffer[SIZE];

    char handshake[] = "raw\r\n\r\n";

    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        exit(-1);
    }

     /* host is deallocated by the socket runtime*/
    if ((host = gethostbyname("127.0.0.1")) == NULL) {
        exit(-1);
    }

    server.sin_family = AF_INET;
    server.sin_port = htons(9090);
    server.sin_addr = *(struct in_addr *) host->h_addr;

    if (0 != connect(sock, (struct sockaddr *) &server, sizeof(server))) {
        exit(-1);
    }

    write(sock, handshake, strlen(handshake));

  len = snprintf(buffer,SIZE,"{\"receiver\":\"/wrtStatus\",\"msg\":{\"data\":%d},\"type\":\"std_msgs/UInt8\"}",status);
  if (len < 0 || len >= SIZE) {
    exit(-1);
  }

  write(sock,"\x00",1);
  write(sock,buffer,len);
  write(sock,"\xFF",1);

    close(sock);

}