Thread: Using fork() to create two childs

Hello,
I have the following code that is supposed a parent and two childs. It works, but it doesn't look right in terms of process creation. I am confused about the part in star comments. Thanks.

Code:

#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>

#define CHILD 1
#define PARENT 0
#define BUF_SIZE 512

void perror_exit(const char *msg)
{
   perror(msg);
   exit(1);
}

void socketpair2(int *sock_fd)
{
  if(socketpair(AF_LOCAL, SOCK_STREAM, 0, sock_fd) < 0)
    perror_exit("socketpair");
}

/*
 * creates a new process and returns return value of fork()
 */ 
int fork2()
{  
  int pid;

  if((pid = fork()) < 0)
    perror("fork"), exit(1);

  return pid;
}

void app_layer(int sock_fd1[], int sock_fd2[])
{
  char buf[BUF_SIZE];
  char buf2[BUF_SIZE];

  buf[0] = 0;
  buf2[0] = 0;
  close(sock_fd1[CHILD]);
  close(sock_fd2[CHILD]);

  strcpy(buf, "APP TO IP/ICMP 1 ");
  if(write(sock_fd1[PARENT], buf, BUF_SIZE) < 0)
    perror_exit("write app_layer");

  strcpy(buf2, "APP TO IP/ICMP 2 ");
  if(write(sock_fd2[PARENT], buf2, BUF_SIZE) < 0)
    perror_exit("write app_layer");

  if(read(sock_fd1[PARENT], buf, BUF_SIZE) < 0)
    perror_exit("read");

  if(read(sock_fd2[PARENT], buf2, BUF_SIZE) < 0)
    perror_exit("read");

  printf("%s\n%s\n", buf, buf2);
}

void ip_icmp_layer(int sock_fd[], char *str)
{
  char buf[BUF_SIZE];

  close(sock_fd[PARENT]);

  if(read(sock_fd[CHILD], buf, BUF_SIZE) < 0)
    perror_exit("read");

  strcat(buf, str);
  strcat(buf, " IP/ICMP TO APP");

  if(write(sock_fd[CHILD], buf, BUF_SIZE) < 0)
    perror_exit("write");
}

int main()
{
  int pid;
  int sock1[2], sock2[2];

  // create a parent with two childs NOT child and grandchild
  socketpair2(sock1);
  socketpair2(sock2);
  pid = fork2();

  if(pid)
  {
//*****************
    pid = fork2();

    if(pid)
      app_layer(sock1, sock2);
    else
      ip_icmp_layer(sock2, "22");
//*****************
  }
  else
    ip_icmp_layer(sock1, "11");

  return 0;
}

No idea - your continual abuse of the language after being told (and having it explained to you) in previous threads makes me think that it's a waste of time even bothering to try.