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

int main()
{
    int data_processed;
    int file_pipes[2];
    const char some_data[] = "123";
    char buffer[BUFSIZ + 1];

    memset(buffer, '\0', sizeof(buffer));

    if (pipe(file_pipes) == 0)
    {
        data_processed = write(file_pipes[1], some_data, strlen(some_data));
        printf("Wrote %d bytes\n", data_processed);
        data_processed = read(file_pipes[0], buffer, BUFSIZ);
        printf("Read %d bytes: %s\n", data_processed, buffer);
        exit(EXIT_SUCCESS);
    }
    exit(EXIT_FAILURE);
}

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

int main()
{
    int data_processed;
    int file_pipes[2];
    const char some_data[] = "123";
    char buffer[BUFSIZ + 1];
    pid_t fork_result;

    memset(buffer, '\0', sizeof(buffer));

    if (pipe(file_pipes) == 0)
    {
        fork_result = fork();
        if (fork_result == -1)
        {
            fprintf(stderr, "Fork failure");
            exit(EXIT_FAILURE);
        }
        /* child */
        if (fork_result == 0)
        {
            data_processed = read(file_pipes[0], buffer, BUFSIZ);
            printf("Read %d bytes: %s\n", data_processed, buffer);
            exit(EXIT_SUCCESS);
        }
        else
        {
            /* parent */
            data_processed = write(file_pipes[1], some_data,
                                   strlen(some_data));
            printf("Wrote %d bytes\n", data_processed);
        }
    }
    exit(EXIT_SUCCESS);
}