I an trying to create a program in c that has one parent process and three child ones. The aim is that the parent will be connected with each child with two pipes so when the children choose to send a message to one of their siblings they will send it first to the parent and then it will send it to the appropriate child. The read ends of the parent have to be non-blocking .

I have tried to follow the example that is in the https://www.geeksforgeeks.org/non-blocking-io-with-pipes-in-c/ site . The two errors that I have are the following: 1)array type has incomplete element type ‘int[]’ void parent_read(int pipes[][]) (line 11)
2)type of formal parameter is incomplete parent_read(pipes); (line140)

What can I do to fix it? And is what I have done till now in regards to non-blocking correct?
Thanks

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <time.h>

#define MSGSIZE 5

void parent_read(int pipes[][])
{
    int nread;
    char buf[MSGSIZE];

    // write link
    close(pipes[1]);

    while (1) {

        // read call if return -1 then pipe is
        // empty because of fcntl
        nread = read(pipes[0], buf, MSGSIZE);
        switch (nread) {
        case -1:

            // case -1 means pipe is empty and errono
            // set EAGAIN
            if (errno == EAGAIN) {
                printf("(pipe empty)n");
                sleep(1);
                break;
            }

            else {
                perror("read");
                exit(4);
            }

        // case 0 means all bytes are read and EOF(end of conv.)
        case 0:
            printf("End of conversationn");

            // read link
            close(pipes[0]);

            exit(0);
        default:

            // text read
            // by default return no. of bytes
            // which read call read at that time
            printf("MSG = %sn", buf);
        }
    }
}



int main()
{
    int pids[3],id[3];
    int pipes[6][2];
    int i;
    for (i=0;i<6;i++)
    {
        if (pipe(pipes[i])==-1)
        {
            printf("Error in pipe: %dn",i);
            return 0;
        }
        else
        {
            printf("Error in pipe:!n");
        }
    }

     if (fcntl(pipes[0][0], F_SETFL, O_NONBLOCK) < 0)
     {
         exit(2);
     }
    for(i=0;i<3;i++)
    {
        pids[i]=fork();

        if(pids[i]==0)
        {
            id[i]=getpid();
            //printf("ID:%dn",id[i]);
             break;
        }
    }
    if (getpid()==id[0])
        {
            for (i=0;i<6;i++)
            {
                if (i>0 && i>1)
                {
                    close(pipes[i][0]);
                    close(pipes[i][1]);
                    printf("Pipes of A have closed:%dn",i);
                }
            }
           /* char* x="hello";
          if (write(pipes[1][1],&x,sizeof(int)) == -1)
            {
               printf("error in  write");
            }*/
            return 0;
        }
    if (getpid()==id[1])
        {
            for (i=0;i<6;i++)
            {
                if ((i>2 && i>3) || (i<2 && i<3))
                {
                    close(pipes[i][0]);
                    close(pipes[i][1]);
                    printf("Pipes of B have closed:%dn",i);
                }
            }
            return 0;
        }
    if (getpid()==id[2])
        {
             for (i=0;i<6;i++)
            {
                if (i<4 && i<5)
                {
                    close(pipes[i][0]);
                    close(pipes[i][1]);
                    printf("Pipes of C have closed:%dn",i);
                }
            }
            return 0;
        }
    if(getpid()!=0)
    {
       // char y;
        parent_read(pipes); //Here i try to call parent read
        //read(pipes[1][0],&y,sizeof(int));
        //printf("The child processe has given:%y",y);
        for(i=0;i<=3;i++)
        {
            wait(NULL);

        }
        printf("PARENT:%dn",getpid());
    }
}