how can i run these two proceses normally in c language?

this code works fine but consumer process does not work, i tried to get producer_pid value and check what is going on but when i write the printf("%d\n",producer_pid) it gives two values when do not put \n it gives one value. i am new to all computer programming i am educating myself, if the question is so bad i am sorry

i think producer process is not ending any idea that could help me?

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define BUFFER_SIZE 2
int buffer[BUFFER_SIZE];
int sayac = 0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
void produce(int item) {
buffer[sayac] = item;
sayac++;
}
int consume() {
int item = buffer[sayac - 1];
sayac--;
return item;
}
void *producer_thread(void *arg) {
int *pipe_fd = (int *)arg;
for (int i = 1; i <= 10; i++) {
pthread_mutex_lock(&mutex);
while (sayac == BUFFER_SIZE) {
pthread_mutex_unlock(&mutex);
usleep(100000);  // Kısa bir süre bekleyerek döngüyü serbest bırak
pthread_mutex_lock(&mutex);
}
produce(i);
printf("Üretici: %d üretildi.\n", i);
write(pipe_fd[1], &i, sizeof(i));
pthread_mutex_unlock(&mutex);
sleep(1);
}
close(pipe_fd[1]);
return NULL;
}
void *consumer_thread(void *arg) {
int *pipe_fd = (int *)arg;
for (int i = 1; i <= 10; i++) {
pthread_mutex_lock(&mutex);
while (sayac == 0) {
pthread_mutex_unlock(&mutex);
usleep(100000);  // Kısa bir süre bekleyerek döngüyü serbest bırak
pthread_mutex_lock(&mutex);
}
int item = consume();
printf("Tüketici: %d tüketildi.\n", item);
int received_data;
read(pipe_fd[0], &received_data, sizeof(received_data));
pthread_mutex_unlock(&mutex);
sleep(1);
}
close(pipe_fd[0]);
return NULL;
}
int main() {
int pipe_fd[2];
if (pipe(pipe_fd) == -1) {
perror("Pipe oluşturulamadı");
return 1;
}
pid_t producer_pid = fork();
printf("%d ---------------",producer_pid);
if (producer_pid == 0) {
// Yavru üretici işlem kodu
close(pipe_fd[0]); // Okuma tarafını kapat
producer_thread((void *)pipe_fd);
exit(0);
} else if (producer_pid > 0) {
pid_t consumer_pid = fork();
if (consumer_pid == 0) {
// Yavru tüketici işlem kodu
close(pipe_fd[1]); // Yazma tarafını kapat
consumer_thread((void *)pipe_fd);
exit(0);
} else if (consumer_pid > 0) {
// Ana işlem kodu
close(pipe_fd[0]); // Okuma tarafını kapat
close(pipe_fd[1]); // Yazma tarafını kapat
wait(NULL);
wait(NULL);
printf("Ana işlem tamamlandı.\n");
} else {
fprintf(stderr, "Tüketici işlem oluşturulamadı.\n");
return 1;
}
} else {
fprintf(stderr, "Üretici işlem oluşturulamadı.\n");
return 1;
}
return 0;
}

the main problem here is that you're opening a pthread mutex to sync between processes opened using fork().

pthread_mutex, as its name would suggest, is designed to sync between threads.
It will not be able to sync between processes created using fork since the processes will have a different memory space.

For your implementation, there isn't much of a point to even use pthread_mutex. write() and read() are blocking, so you can have both processes sync by using the pipe.

On a different subject, when you use printf(), sometimes the OS will wait and not print all of the log. use fflush() to see all your logs.