exit_status_alternative.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.
 *
 ********************************************************
 * exit_status_alternative.c
 *
 * Simple code to demonstrate thread exit status: Passes
 * back address to status code.  Safer method when there's
 * a posibility of threads being cancelled, because addresses
 * won't conflict with PTHREAD_CANCELED
 */
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <pthread.h>

pthread_t thread;

static int arg;
static const int real_bad_error = -12;
static const int normal_error = -10;
static const int success = 1;

void * routine_x(void *arg_in)
{
	int *arg = (int *)arg_in;
	
	if (*arg == 1) 
	{
		pthread_exit((void *)real_bad_error);
	} 
	else if (*arg == 2) 
	{
		return ((void *)normal_error);
	} 
	else 
	{
		return ((void *)success);
	}
}

extern int main(int argc, char **argv)
{
	extern int arg;
	pthread_t thread;
	void *status;
	
	if (argc < 2)
		printf("usage: %s [1-3]\n", argv[0]), exit(1);
	
	arg = atoi(argv[1]);
	
	pthread_create(&thread, NULL, routine_x, &arg);
	
	pthread_join(thread, &status);
	if (status == PTHREAD_CANCELED) 
	{
		printf("Thread was canceled.\n");
	}
	else 
	{
		printf("Thread completed and exit status is %ld.\n", (int)status);
	}
	
	return 0;
}