semaphore.h

#ifndef _SEMAPHORE_H
#define _SEMAPHORE_H

#include <stdlib.h>
#include <pthread.h>

typedef struct semaphore{
  pthread_mutex_t lock;
  pthread_cond_t signal;
  int value;
} semaphore_t;

semaphore_t * initialize(int value);
void prolaag(semaphore_t *sem, pthread_mutex_t *waitLock);
void verhoog(semaphore_t *sem);



#endif



semaphore.c 
#include "semaphore.h"

semaphore_t  * initialize(int value){
  semaphore_t *temp;
  temp = (semaphore_t*)malloc(sizeof(semaphore_t));

  temp->lock = PTHREAD_MUTEX_INITIALIZER;
  temp->signal = PTHREAD_COND_INITIALIZER;
  temp->value = value;
  
  return temp;
}
  
void prolaag(semaphore_t *sem, pthread_mutex_t *waitLock){
  if (pthread_mutex_lock(&sem->lock))
    exit(0); // exits if mutex fails
  
  sem->value= sem->value - 1;
  
  if (sem->value < 0){
    pthread_mutex_unlock(&sem->lock);
    pthread_mutex_unlock(waitLock);
    pthread_cond_wait(&sem->signal, &sem->lock);
  }
  pthread_mutex_unlock(&sem->lock);
}

void verhoog(semaphore_t *sem){
  if (pthread_mutex_lock(&sem->lock))
      exit(0); // exits if mutex fails

  sem->value = sem->value + 1;
    
  if(sem->value <= 0)
    pthread_cond_signal(&sem->signal);
  
  
  pthread_mutex_unlock(&sem->lock);
}



error
lest0039@lind24-12 (~/csci5103/posix) % make
gcc -g -Wall   -c -o semaphore.o semaphore.c
semaphore.c: In function ‘initialize’:
semaphore.c:9: error: syntax error before ‘{’ token
semaphore.c:9: warning: control reaches end of non-void function
semaphore.c: At top level:
semaphore.c:10: error: syntax error before ‘->’ token
semaphore.c:11: error: syntax error before ‘->’ token
make: *** [semaphore.o] Error 1
lest0039@lind24-12 (~/csci5103/posix) %