specific.c

linux下多线程程序设计,包括signals,mutex,simple_once

/********************************************************
 * An example source module to accompany...
 *
 * "Using POSIX Threads: Programming with Pthreads"
 *     by Brad nichols, Dick Buttlar, Jackie Farrell
 *     O'Reilly & Associates, Inc.
 *
 ********************************************************
 * specific.c
 *
 */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>

#include <pthread.h>

#define NUM_THREADS  3
pthread_key_t     saved_time_key;


void free_time(void *arg )
{
	struct timeval *timep=(struct timeval *)arg; 
	printf("free_time:\n");
	free(timep);
}

void save_the_time(void)
{
	struct timeval *timep;
	
	timep = (struct timeval *)malloc(sizeof(struct timeval));	
	gettimeofday(timep, (void *)0);	
	printf("save_the_time: \t\t%ld %ld\n",timep->tv_sec, timep->tv_usec);		
	pthread_setspecific(saved_time_key, (void *)timep);
}

void what_time_did_i_save(void)
{
	int rtn;
	
	struct timeval *timep;
	timep = pthread_getspecific(saved_time_key);
	printf("what_time_did_i_save: \t%ld %ld\n",timep->tv_sec, timep->tv_usec);
}  

void *thread_routine(void *arg)
{
	int *my_id=(int *)arg;
	
	printf("thread_routine %d\n", *my_id);	
	save_the_time();	
	what_time_did_i_save();
	
	return(NULL); 
}

extern int 	main(void)
{
	int       i, *id_arg;
	pthread_t threads[NUM_THREADS];
	
	id_arg = (int *)malloc(NUM_THREADS*sizeof(int));
	
	printf("main : initializing the key\n");
	pthread_key_create(&saved_time_key, free_time);
	
	printf("main : spawing the threads\n");
	for (i = 0; i < NUM_THREADS; i++) 
	{	
		id_arg[i] = i;
		pthread_create(&(threads[i]), NULL, thread_routine, (void *) &(id_arg[i]));
	}
	
	for (i = 0; i < NUM_THREADS; i++) 
	{
		pthread_join(threads[i], NULL);
		printf("main : thread %d has finished. \n", i);
	}
	printf("main : goodbye\n");
	
	return 0;
}