Semaphore - Reader Writer Problem

semaphore.c

#include<stdio.h>
#include<pthread.h>
#include<semaphore.h>

sem_t mutex,writeblock;
int data = 0,rcount = 0;

void *reader(void *arg)
{
  int f;
  f = ((int)arg);
  sem_wait(&mutex);
  rcount = rcount + 1;
  if(rcount==1)
   sem_wait(&writeblock);
  sem_post(&mutex);
  printf("Data read by the reader%d is %d\n",f,data);
  sleep(1);
  sem_wait(&mutex);
  rcount = rcount - 1;
  if(rcount==0)
   sem_post(&writeblock);
  sem_post(&mutex);
}

void *writer(void *arg)
{
  int f;
  f = ((int) arg);
  sem_wait(&writeblock);
  data++;
  printf("Data writen by the writer%d is %d\n",f,data);
  sleep(1);
  sem_post(&writeblock);
}

int main()
{
  int i,b; 
  pthread_t rtid[5],wtid[5];
  sem_init(&mutex,0,1);
  sem_init(&writeblock,0,1);
  for(i=0;i<=2;i++)
  {
    pthread_create(&wtid[i],NULL,writer,(void *)i);
    pthread_create(&rtid[i],NULL,reader,(void *)i);
  }
  for(i=0;i<=2;i++)
  {
    pthread_join(wtid[i],NULL);
    pthread_join(rtid[i],NULL);
  }
  return 0;
}

How can I solve this problem using shared_mutex?

I figured it out. Thank you.

…

On Fri, Apr 10, 2020 at 10:38 AM jprustom ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ How can I solve this problem using shared_mutex? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <https://gist.github.com/6209a575f00b122fe490#gistcomment-3248877>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ALC3CNFTZSE2JAJ6655OKQ3RL4VOZANCNFSM4HK6C4BA> .

it is binary semaphore