pipe.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h> // for pipe()
#include <string.h>
#include <time.h>


//
// unnamed pipe example
//
int main(int argc, char *argv[])
{

    srand(time(NULL));
    int r = (rand() % 10)+1;
    printf("%d\n",r);

    int tomb[r];
    int i;
    for(i = 0; i < r; i++){
        tomb[i] = rand() % 10;
    }

    for(i = 0; i < r; i++){
        printf("tomb elemeke: %d\n", tomb[i]);
    }

    int pipefd[2]; // unnamed pipe file descriptor array
    int pipefd2[2]; // unnamed pipe file descriptor array
    pid_t pid;
    char sz[100];  // char array for reading from pipe

    if (pipe(pipefd) == -1 || pipe(pipefd2)) {
        perror("Hiba a pipe nyitaskor!");
        exit(EXIT_FAILURE);
    }
    pid = fork();    // creating parent-child processes
    if (pid == -1) {
        perror("Fork hiba");
        exit(EXIT_FAILURE);
    }

    if (pid == 0){ //1 az iró, 0 az olvasó? pipe = olvasó és író vége van
        // child process
        //sleep(3);    // sleeping a few seconds, not necessary - nem kéne erőltetni
        //close(pipefd[1]);  //Usually we close the unused write end
        printf("Gyerek elkezdi olvasni a csobol az adatokat!\n");
        int i = 0;
        while(read(pipefd[0],sz,sizeof(sz))){
            printf("Gyerek olvasta uzenet: %s\n",sz);
            //write(pipefd2[1],"Hajra vasas\n",12);
            write(pipefd2[1],*tomb[i],sizeof(tomb[i]));
            i++;
        }; // reading max 100 chars - read addig vár, ameddig nem érkezik adat -> szinkronizálás

        close(pipefd[0]); // finally we close the used read end
        close(pipefd2[1]);
    }
    else{    // szulo process
        //sleep(3);
        printf("Szulo indul!\n");

        //close(pipefd[0]); //Usually we close unused read end
        int i = 0;
        while(i < r){
            //write(pipefd[1], "Hajra Fradi!",13); //13 = tobábbítandó karakterek száma
            write(pipefd[1],*tomb[i],sizeof(tomb[i])); //13 = tobábbítandó karakterek száma
            read(pipefd2[0],sz,sizeof(sz));
            printf("Szülő olvasta uzenet: %s\n",sz);
            i++;
        }
        close(pipefd[1]); // Closing write descriptor
        close(pipefd2[0]);
        printf("Szulo beirta az adatokat a csobe!\n");
        fflush(NULL);     // flushes all write buffers (not necessary)
        //wait();        // waiting for child process (not necessary)
        // try it without wait()
        printf("Szulo befejezte!\n");
    }
    exit(EXIT_SUCCESS);    // force exit, not necessary
}