#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <pthread.h>
#include <limits.h>
#include <semaphore.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/ipc.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#define THR_AMOUNT 1

char *semName = "/testSem";
struct timespec t;

void *funcA(void *parm){
	sem_t *binSem;
 	if ((binSem = sem_open(semName, O_CREAT)) == SEM_FAILED){
	  	perror("cannot open Semaphore"); 
	  	exit(1);
 	}
	printf("semAdress: %p\n", binSem);
	printf("starting Thread A\n");	
	clock_gettime(CLOCK_REALTIME, &t);
	//while (sem_wait(binSem) == -1 && errno == EINTR)
	//  ;
	t.tv_sec += 5;
	sem_timedwait(binSem, &t);	
	printf("finishing Thread A\n");
 	sem_close(binSem);
	pthread_exit(NULL);
}

int main(int argc, char **argv)
{	
	int co,rc;	
	pthread_t testThread[THR_AMOUNT];
 	pthread_attr_t thrAttr;	
 	struct sched_param param = { .sched_priority = 99 };
	sem_t *binSem;
 	if (mlockall(MCL_CURRENT | MCL_FUTURE) == -1) {
 		perror("could not lock memeory\n");
 		exit(1);
 	}
 	if ((binSem = sem_open(semName, O_CREAT)) == SEM_FAILED){
	  	perror("cannot open Semaphore"); 
	  	exit(1);
 	}
	printf("semAdress: %p\n", binSem);
	sem_post(binSem);
 	sem_wait(binSem); 	
	pthread_attr_init(&thrAttr);
 	pthread_attr_setdetachstate(&thrAttr,PTHREAD_CREATE_JOINABLE);
 	pthread_attr_setinheritsched(&thrAttr,PTHREAD_EXPLICIT_SCHED);	
 	pthread_attr_setschedpolicy(&thrAttr,SCHED_FIFO); 
 	pthread_attr_setschedparam(&thrAttr,&param); 
	if ( (rc = pthread_create(&testThread[0],&thrAttr, funcA, NULL))
 	     != 0 ){
 	        fprintf(stderr, "cannot create Threads %s\n", strerror(rc)); 
 		exit(1);
 	}
 	for ( co = 0; co < THR_AMOUNT; co++) {
 		if ( pthread_join(testThread[co], NULL) != 0 ){
 			perror("cannot join Threads");			
 			exit(1);
 		}
 	}
 	if (munlockall() == -1){
 		perror("munlockall failure");
 		exit(1);
 	}
 	sem_close(binSem);
	sem_unlink(semName);
	return 0;
}