[OS] pthread.h 실행 명령어

#include <pthread.h>
#include <semaphore.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define ITER 1000
void *thread_increment(void * arg);
void *thread_decrement(void * arg);
int x;
sem_t s;

int main() {
	pthread_t tid1, tid2;
	sem_init(&s, 0, 1);
	pthread_create(&tid1, NULL, thread_increment, NULL);
	pthread_create(&tid2, NULL, thread_decrement, NULL);
	
	pthread_join(tid1, NULL);
	pthread_join(tid2, NULL);
	
	if (x != 0 ) printf("boom! counter=%d\n", x);
	else printf("ok counter=%d\n", x);
	
	sem_destroy(&s);
}

void * thread_increment(void *arg) {
	int i, val;
	for (i = 0; i < ITER; i++) {
		sem_wait(&s);
		val = x;
		printf("%u:		%d\n", (unsigned int) pthread_self(), val);
		x = val + 1;
		sem_post(&s);
	}
	return NULL;
}

void * thread_decrement(void *arg) {
	int i, val;
	for (i = 0; i < ITER; i++) {
		sem_wait(&s);
		val = x;
		printf("%u:		%d\n", (unsigned int) pthread_self(), val);
		x = val - 1;
		sem_post(&s);
	}
	return NULL;
}

gcc thread.c -lpthread 해줘야한다.