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My Goal is to get outputs from Dining Philosophers C Program. I am using Visual Studio 2013 on Windows 7 to compile and execute C programs. Got errors stating that pthread.h, semaphore.h were not available. Downloaded the same for windows build and included in the project.

Now I get the following 8 errors

warning C4013: 'sleep' undefined; assuming extern returning int

error LNK2019: unresolved external symbol __imp__sem_init referenced in function _main

error LNK2019: unresolved external symbol __imp__sem_wait referenced in function _put_fork

error LNK2019: unresolved external symbol __imp__sem_post referenced in function _put_fork

error LNK2019: unresolved external symbol __imp__pthread_create referenced in function _main

error LNK2019: unresolved external symbol __imp__pthread_join referenced in function _main

error LNK2019: unresolved external symbol _sleep referenced in function _philospher

error LNK1120: 6 unresolved externals

The Code I have used is`

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

#define N 5
#define THINKING 0
#define HUNGRY 1
#define EATING 2
#define LEFT (ph_num+4)%N
#define RIGHT (ph_num+1)%N

sem_t mutex;
sem_t S[N];

void * philospher(void *num);
void take_fork(int);
void put_fork(int);
void test(int);

int state[N];
int phil_num[N] = { 0, 1, 2, 3, 4 };

int main()
{
    int i;
    pthread_t thread_id[N];
    sem_init(&mutex, 0, 1);
    for (i = 0; i<N; i++)
        sem_init(&S[i], 0, 0);
    for (i = 0; i<N; i++)
    {
        pthread_create(&thread_id[i], NULL, philospher, &phil_num[i]);
        printf("Philosopher %d is thinking\n", i + 1);
    }
    for (i = 0; i<N; i++)
        pthread_join(thread_id[i], NULL);
}

void *philospher(void *num)
{
    while (1)
    {
        int *i = num;
        sleep(1);
        take_fork(*i);
        sleep(0);
        put_fork(*i);
    }
}

void take_fork(int ph_num)
{
    sem_wait(&mutex);
    state[ph_num] = HUNGRY;
    printf("Philosopher %d is Hungry\n", ph_num + 1);
    test(ph_num);
    sem_post(&mutex);
    sem_wait(&S[ph_num]);
    sleep(1);
}

void test(int ph_num)
{
    if (state[ph_num] == HUNGRY && state[LEFT] != EATING && state[RIGHT] != EATING)
    {
        state[ph_num] = EATING;
        sleep(2);
        printf("Philosopher %d takes fork %d and %d\n", ph_num + 1, LEFT + 1, ph_num + 1);
        printf("Philosopher %d is Eating\n", ph_num + 1);
        sem_post(&S[ph_num]);
    }
}

void put_fork(int ph_num)
{
    sem_wait(&mutex);
    state[ph_num] = THINKING;
    printf("Philosopher %d putting fork %d and %d down\n", ph_num + 1, LEFT + 1, ph_num + 1);
    printf("Philosopher %d is thinking\n", ph_num + 1);
    test(LEFT);
    test(RIGHT);
    sem_post(&mutex);
}`
leppie
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1 Answers1

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It is too late, but today I faced this problem too. Problem: I can't use pthread in window platform. Solution: find another variant of pthreadVC2.lib in C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\lib (for me it was x86 instead of x64)

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user7679864
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