Linux C编程例子

				#include  
				#include  
				pthread_once_t once=PTHREAD_ONCE_INIT; 
				void once_run(void) 
				{ 
				  printf("once_run in thread %d\n",pthread_self()); 
				} 
				void * child1(void *arg) 
				{ 
				  int tid=pthread_self(); 
				  printf("thread %d enter\n",tid); 
				  pthread_once(&once,once_run); 
				  printf("thread %d returns\n",tid); 
				} 
				void * child2(void *arg) 
				{ 
				  int tid=pthread_self(); 
				  printf("thread %d enter\n",tid); 
				  pthread_once(&once,once_run); 
				  printf("thread %d returns\n",tid); 
				} 
				int main(void) 
				{ 
				  int tid1,tid2; 
				  printf("hello\n"); 
				  pthread_create(&tid1,NULL,child1,NULL); 
				  pthread_create(&tid2,NULL,child2,NULL); 
				  sleep(10); 
				  printf("main thread exit\n"); 
				  return 0; 
				}