Parallel pipe issue when closing in c

Question

I am currently working on a project where I need to create multiple fork who read from different pipe until the pipe closed. The issue here is that if I create more than one pipe, even if I close both side of all the pipe the child are still stuck on read.

Here is a simplify version of my code with the same issue:

#include <stdlib.h>
#include <unistd.h>

#define NB_PIPES 2

void    read_write_pipe(int pipefd[2]) { //write what goes through is pipe until it closed
    char buf;

    close(pipefd[1]); //close the writing part of the tube
    while (read(pipefd[0], &buf, 1) > 0)
        write(1, &buf, 1);
    close(pipefd[0]);
    _exit(EXIT_SUCCESS);
}

int main(void)
{
    int pipefd[NB_PIPES][2];
    pid_t cpid;

    for (int i = 0; i < NB_PIPES; i++) { //I create my pype
        pipe(pipefd[i]);
    }
    for (int i = 0; i < NB_PIPES; i++) {
        cpid = fork();
        if (cpid == 0)
            read_write_pipe(pipefd[i]); //create fork who will read from pipe i
        else {
            close(pipefd[i][0]); //close the reading part of pipe i
        }
    }
    for (int i = 0; i < NB_PIPES; i++) {
        write(pipefd[i][1], "Salut\n", 6); //write through pipe i
        close(pipefd[i][1]); //close the writing part of pipe i
    }
    for (int i = 0; i < NB_PIPES; i++) {
        wait(NULL);
    }
    return (0);
}

I compile with ggc

Thanks for reading and for the help !

Answer 1

So thanks to Bodo I found the issue Here is a correct version of the code:

#include <stdlib.h>
#include <unistd.h>

#define NB_PIPES 2

void    read_write_pipe(int pipefd[NB_PIPES][2], int i) { //write what goes through is pipe until it closed
    char buf;

    for (int j = 0; j < NB_PIPES; j++) {
        if (j != i) {
            close(pipefd[j][0]); //close all the other pipe
            close(pipefd[j][1]);
        }
    }
    close(pipefd[i][1]); //close the writing part of the tube
    while (read(pipefd[i][0], &buf, 1) > 0)
        write(1, &buf, 1);
    close(pipefd[i][0]);
    _exit(EXIT_SUCCESS);
}

int main(void)
{
    int pipefd[NB_PIPES][2];
    pid_t cpid;

    for (int i = 0; i < NB_PIPES; i++) { //I create my pype
        pipe(pipefd[i]);
    }
    for (int i = 0; i < NB_PIPES; i++) {
        cpid = fork();
        if (cpid == 0)
            read_write_pipe(pipefd, i); //create fork who will read from pipe i
        else {
            close(pipefd[i][0]); //close the reading part of pipe i
        }
    }
    sleep(1);
    for (int i = 0; i < NB_PIPES; i++) {
        write(pipefd[i][1], "Salut\n", 6); //write through pipe i
        close(pipefd[i][1]); //close the writing part of pipe i
    }
    for (int i = 0; i < NB_PIPES; i++) {
        wait(NULL);
    }
    return (0);
}

Thanks for the help !