Problem when writing characters into file in C

Question

I have a problem I'm trying to run a program that have a user defined number of consumer and clients. The pipe works fine but the problem is that between characters I have a filename of the file that I'm writing to. It generates a good number of chars client get it right too. Between chars in client there is a client file name and between chars in consument there is consument file name. File contains "S/prod/prod-92721W/prod/prod-92721X". The second problem is that all producents have the same char generated and I wanted to have a different set of char for every producent.

Can somebody explain what I'm doing wrong

#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/sem.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>
#include <sys/param.h>

void tworz_konsumentow (int *potok, long ilekonsum);
void tworz_producentow (int *potok, long ileproducentow, long ileznakow);
void wygeneruj_plik (int ile_znakow);

void init(int argc, char **argv, long *ileproducentow, long *ilekonsum, long *ileznakow)
{
        
    if(argc!=4)
    {
        printf("Z?a ilo?? argumentów");
        exit(1);""
    }
    char *koniec;
    *ileproducentow = strtol(argv[1], &koniec, 10); //konwertuje wszystko na posta? liczbow? typu long
    *ilekonsum = strtol(argv[2], &koniec, 10);
    *ileznakow = strtol(argv[3], &koniec , 10);
    if(*ileznakow <=0 || *ileproducentow <=0 || *ilekonsum <=0)
    {
        printf("Podano z?? warto?c argumentu");
        exit(1);
    }
}

int main(int argc, char **argv)
{
    long ileproducentow , ilekonsum, ileznakow;
    init(argc, argv, &ileproducentow, &ilekonsum, &ileznakow);

    int potok[2];
    if (pipe(potok) == -1)
    {
        perror("Error is: ");
        exit(1);
    }

    tworz_producentow(potok, ileproducentow, ileznakow);
    tworz_konsumentow(potok, ilekonsum);
    close(potok[0]);
    close(potok[1]);

}

void tworz_producentow (int *potok, long ileproducentow, long ileznakow)
{
    srand(time(NULL));
    FILE *file ;
    int zapis ;
    char znak[1] ;
    for (int i; i<ileproducentow; i++)
    {
        switch(fork())
        {
            case -1:
                perror("Fork error:");
                exit(1);
            case 0:
                close(potok[0]); //blokuje czytanie drugiemu procesowi

                char filename[sizeof("./prod/prod-95844.txt")] ;
                sprintf(filename,"./prod/prod-%d.txt",getpid());
                file = fopen(filename, "a");
                for (int j=0; j<ileznakow; j++)
                {
                    znak[0] = 'A' + (random() % 26);
                    fputs(znak, file);
                    zapis = write(potok[1], znak, 1); //write wpisuje znak do potoku
                    if (zapis == -1)
                    {
                        perror("error is:");
                        fclose(file);
                        exit(1);
                    }
                }
                close(potok[1]);
                fclose(file);
                exit(0);
        }
    }
}

void tworz_konsumentow(int *potok, long ilekonsum)
{
    int desc;
    char znak[1];
    FILE *file;
    for (int i = 0 ; i < ilekonsum; i++)
    {
        switch(fork())
        {
            case -1:
                perror("Fork error:");
                exit(1);
            case 0:
                close(potok[1]);
                char filename[sizeof("./cons/cons-95844.txt")] ;
                sprintf(filename,"./cons/cons-%d.txt",getpid());
                file = fopen(filename, "a");
                while(1)
                {
                    desc = read(potok[0], znak, 1); // 
                    if (desc == 0)
                    {
                        close(potok[0]);
                        fclose(file);
                        exit(1);
                    }
                    else if (desc == -1)
                    {
                        perror ("Blad odczytu danych z potoku");
                        fclose(file);
                        exit(1);
                    }
                    else
                    {
                        fputs(znak, file);
                    }
                    
                }          
        }
    }
}

question from:https://stackoverflow.com/questions/65878735/problem-when-writing-characters-into-file-in-c

Answer 1

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