多线程产生竞争条件

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

int i = 1;
void *f1()
{
if(i==1)
{
sleep(3);
}
if(i == 2)
{
printf(“hack it!\n”);
}
else
{
printf(“you can try it again”);
}
}
void *f2()
{
sleep(1);
i = 2;
}
int main()
{
pthread_t id1,id2;

pthread_create(&id1,NULL,(void*)f1,NULL);
pthread_create(&id1,NULL,(void*)f2,NULL);

pthread_join(id1,NULL);
pthread_join(id2,NULL);

return 0;

}